EOT Eaton Vance National Municipal Opportunities Trust

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Item 1. Reports to Stockholders

 

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Eaton Vance

National Municipal Opportunities Trust (EOT)

Annual Report

March 31, 2024

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Commodity Futures Trading Commission Registration.

The Commodity Futures Trading Commission (“CFTC”) has adopted regulations that subject registered investment companies and advisers to regulation by the CFTC if a fund invests more than a prescribed level of its assets in certain CFTC-regulated instruments (including futures, certain options and swap agreements) or markets itself as providing investment exposure to such instruments. The investment adviser has claimed an exclusion from the definition of “commodity pool operator” under the Commodity Exchange Act with respect to its management of the Fund. Accordingly, neither the Fund nor the adviser with respect to the operation of the Fund is subject to CFTC regulation. Because of its management of other strategies, the Fund’s adviser is registered with the CFTC as a commodity pool operator. The adviser is also registered as a commodity trading advisor.

Fund shares are not insured by the FDIC and are not deposits or other obligations of, or guaranteed by, any depository institution. Shares are subject to investment risks, including possible loss of principal invested.

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Annual Report

March 31, 2024

Eaton Vance

National Municipal Opportunities Trust

Table of Contents
Management’s Discussion of Fund Performance	2
Performance	3
Fund Profile	4
The Fund’s Investment Objectives, Principal Strategies and Principal Risks	5
Summary of Fund Expenses	13
Trading and NAV Information	14
Endnotes and Additional Disclosures	15
Financial Statements	16
Report of Independent Registered Public Accounting Firm	31
Federal Tax Information	32
Annual Meeting of Shareholders	33
Dividend Reinvestment Plan	34
Management and Organization	36
U.S. Customer Privacy Notice	39
Important Notices	42

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Table of Contents

Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

Management’s Discussion of Fund Performance

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Economic and Market Conditions

The 12-month period ended March 31, 2024, began with an April 2023 municipal bond sell-off that continued through much of the period. Although positive technical factors -- particularly municipal bond demand that exceeded supply -- produced brief periods of positive performance, the U.S. Federal Reserve’s (the Fed’s) 10th and 11th interest rate hikes in just over a year -- in May and July 2023 -- contributed to rising municipal yields and falling bond prices.

From August through October 2023, above-average supplies of municipal bonds -- plus an end-of-summer slowdown in coupon reinvestment -- reduced demand for municipal bonds. Although the Fed left the federal funds rate unchanged in September 2023, investors interpreted the central bank’s message to be that rates might stay higher for longer than they had expected just weeks earlier -- adding fuel to the municipal bond sell-off.

However, in November and December 2023, the municipal bond market reversed course. After several months of rising interest rates and negative bond returns, federal tax-free municipal yields approached their 2022 highs, giving investors a compelling reason to buy tax-exempt municipal bonds.

Typical calendar year-end technical factors -- particularly constrained supplies and increased investor demand -- were additional tailwinds for municipal bond prices. Falling inflation and easing employment gains also led many investors to believe the Fed might be done raising interest rates. Such factors contributed to the Bloomberg Municipal Bond Index (the Index) returning 6.35% in November 2023, its best monthly performance since 1982.

In December 2023, the Index posted another solid monthly gain as investors began to conclude the Fed might begin lowering interest rates during the first half of 2024.

In the final three months of the period, however, municipal returns turned negative as municipal bonds -- following a strong year-end rally -- appeared overvalued relative to U.S. Treasurys. Fed statements and strong U.S. economic reports in early 2024 led investors to reduce expectations for the number of Fed rate cuts projected for the year and how soon they might begin. As a result, both municipal bonds and U.S. Treasurys delivered negative performance during the first quarter of 2024.

For the period as a whole, the Index returned 3.13%, as municipal bonds outperformed U.S. Treasurys throughout the yield curve. Although yields rose and prices fell across the municipal bond yield curve, the positive contribution from rising interest income outweighed the negative effect of falling bond prices. During the period, lower-rated bonds generally outperformed higher-rated bonds, while longer-maturity bonds generally outperformed shorter-maturity bonds.

Fund Performance

For the 12-month period ended March 31, 2024, Eaton Vance National Municipal Opportunities Trust (the Fund) returned 5.60% at net asset value of its common shares (NAV), outperforming its benchmark, the Bloomberg Municipal Bond Index (the Index), which returned 3.13%. 

The Fund’s primary investment objective is to provide current income exempt from federal income tax. Capital appreciation is a secondary objective.

During normal market conditions, the Fund will invest at least 80% of its gross assets in debt obligations issued by or on behalf of states, territories and possessions of the U.S., including the District of Columbia, and their political subdivisions, agencies or instrumentalities, the interest on which is exempt from regular federal income tax (“municipal obligations”), including investments in residual interest bonds whose interest is exempt from regular federal income tax. During normal market conditions, at least 70% of the Fund’s investments in municipal obligations will be rated investment-grade quality -- Baa/BBB or higher by Moody’s, S&P, or Fitch -- at the time of investment.

Contributors to Fund performance relative to the Index included an overweight position in bonds rated BBB and below, as lower-rated bonds generally outperformed higher-rated bonds during the period. 

The Fund also benefited from security selections and an overweight position in industrial development revenue bonds -- the best-performing sector within the Index during the period -- and an overweight position in bonds with 17 years or more remaining to maturity, during a period when longer-maturity bonds generally outperformed shorter-maturity bonds.

In contrast, security selections in Hawaii bonds and security selections in bonds subject to the alternative minimum tax (AMT) detracted from Fund performance versus the Index during the period.

See Endnotes and Additional Disclosures in this report.

Past performance is no guarantee of future results. Returns are historical and are calculated net of management fees and other expenses by determining the percentage change in net asset value (NAV) or market price (as applicable) with all distributions reinvested in accordance with the Fund’s Dividend Reinvestment Plan. Furthermore, returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Performance at market price will differ from performance at NAV due to variations in the Fund’s market price versus NAV, which may reflect factors such as fluctuations in supply and demand for Fund shares, changes in Fund distributions, shifting market expectations for the Fund’s future returns and distribution rates, and other considerations affecting the trading prices of closed-end funds. Investment return and principal value will fluctuate so that shares, when sold, may be worth more or less than their original cost. Performance for periods less than or equal to one year is cumulative. Performance is for the stated time period only; due to market volatility, current Fund performance may be lower or higher than the quoted return. For performance as of the most recent month-end, please refer to eatonvance.com.

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Table of Contents

Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

Performance

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Portfolio Manager(s)

Cynthia J. Clemson and William J. Delahunty, Jr., CFA

% Average Annual Total Returns 1,2	Inception Date	One Year	Five Years	Ten Years
Fund at NAV	05/29/2009	5.60%	1.50%	3.23%
Fund at Market Price	—	(1.82)	(0.71)	3.18
Bloomberg Municipal Bond Index	—	3.13%	1.59%	2.66%

% Premium/Discount to NAV 3
As of period end	(10.32)%

Distributions 4
Total Distributions per share for the period	$0.75
Distribution Rate at NAV	4.05%
Taxable-Equivalent Distribution Rate at NAV	6.85
Distribution Rate at Market Price	4.52
Taxable-Equivalent Distribution Rate at Market Price	7.64

% Total Leverage 5
Residual Interest Bond (RIB) Financing	12.09%

Growth of $10,000

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This graph shows the change in value of a hypothetical investment of $10,000 in the Fund for the period indicated. For comparison, the same investment is shown in the indicated index.

See Endnotes and Additional Disclosures in this report.

Past performance is no guarantee of future results. Returns are historical and are calculated net of management fees and other expenses by determining the percentage change in net asset value (NAV) or market price (as applicable) with all distributions reinvested in accordance with the Fund’s Dividend Reinvestment Plan. Furthermore, returns do not reflect the deduction of taxes that shareholders may have to pay on Fund distributions or upon the sale of Fund shares. Performance at market price will differ from performance at NAV due to variations in the Fund’s market price versus NAV, which may reflect factors such as fluctuations in supply and demand for Fund shares, changes in Fund distributions, shifting market expectations for the Fund’s future returns and distribution rates, and other considerations affecting the trading prices of closed-end funds. Investment return and principal value will fluctuate so that shares, when sold, may be worth more or less than their original cost. Performance for periods less than or equal to one year is cumulative. Performance is for the stated time period only; due to market volatility, current Fund performance may be lower or higher than the quoted return. For performance as of the most recent month-end, please refer to eatonvance.com.

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Table of Contents

Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

Fund Profile

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Credit Quality (% of total investments) 1,2

Footnotes:

1

For purposes of the Fund’s rating restrictions, ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”), as applicable. If securities are rated differently by the ratings agencies, the highest rating is applied. Ratings, which are subject to change, apply to the creditworthiness of the issuers of the underlying securities and not to the Fund or its shares. Credit ratings measure the quality of a bond based on the issuer’s creditworthiness, with ratings ranging from AAA, being the highest, to D, being the lowest based on S&P’s measures. Ratings of BBB or higher by S&P or Fitch (Baa or higher by Moody’s) are considered to be investment-grade quality. Credit ratings are based largely on the ratings agency’s analysis at the time of rating. The rating assigned to any particular security is not necessarily a reflection of the issuer’s current financial condition and does not necessarily reflect its assessment of the volatility of a security’s market value or of the liquidity of an investment in the security. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above.

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The chart includes the municipal bonds held by a trust that issues residual interest bonds, consistent with the Portfolio of Investments.

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Table of Contents

Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

The Fund's Investment Objectives, Principal Strategies and Principal Risks

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Investment Objectives. 

The Fund’s primary investment objective is to provide current income exempt from federal income tax. Capital appreciation is a secondary objective.

Principal Strategies. 

During normal market conditions, the Fund will invest at least 80% of its gross assets in debt obligations issued by or on behalf of states, territories and possessions of the United States, including the District of Columbia, and their political subdivisions, agencies or instrumentalities, the interest on which is exempt from regular federal income tax (“municipal obligations”). For purposes of this 80% policy, municipal obligations will include investments in residual interest bonds whose interest is exempt from regular federal income tax.

During normal market conditions, at least 70% of the Fund’s investments in municipal obligations will be investment grade quality at time of investment. A municipal obligation is considered investment grade quality if it is either (i) rated within the four highest ratings categories by at least one nationally recognized statistical rating organization (a “Rating Agency”), which are those rated Baa or higher by Moody’s Investors Service, Inc. (“Moody’s”) or BBB or higher by Standard & Poor’s Ratings Services (“S&P”) or Fitch Ratings (“Fitch”), or (ii) an unrated municipal obligation that the Fund’s investment adviser considers to be of investment grade quality. If a municipal obligation is rated differently by two or more Rating Agencies, the Fund will use the higher of such ratings (the “Municipal Obligation Rating”). If a municipal obligation is insured, the Fund will use the higher of the Municipal Obligation Rating or the insurance issuer’s rating. Securities rated in the fourth highest category (i.e., Baa by Moody’s or BBB by S&P or Fitch) are considered investment grade quality, but may have speculative characteristics.

Up to 30% of the Fund’s investments in municipal obligations may be below investment grade quality at time of investment. A municipal obligation is considered below investment grade quality if it is either (i) rated below investment grade by a Rating Agency, or (ii) an unrated municipal obligation that the Fund’s investment adviser considers to be of comparable quality. Municipal obligations of below investment grade quality (commonly referred to as “junk” bonds) involve special risks as compared to municipal obligations of investment grade quality. These risks include greater sensitivity to a general economic downturn, greater market price volatility and less secondary market trading. The Fund may invest in below investment grade municipal obligations of any quality. This means that the Fund’s investments in municipal obligations may include securities of issuers that are having financial difficulties, which may include being in default on obligations to pay principal or interest thereon when due or involved in bankruptcy or insolvency proceedings (such securities are commonly referred to as “distressed securities”). While the Fund is not limited in its exposure to any issuer or obligor, the Fund generally will not invest more than 2% of its gross assets in any single security of below investment grade quality. Under normal market conditions, the Fund will seek to maintain an average credit quality of investment grade.

Up to 20% of the Fund’s investments in municipal obligations may be subject to the alternative minimum tax. Up to 5% of the Fund’s investments in municipal obligations may be collateralized by the proceeds from class action or other litigation against the tobacco industry. Such municipal obligations are backed solely by expected revenues to be derived from lawsuits involving tobacco-related deaths and illnesses which were settled between certain states and American tobacco companies. The Fund invests in residual interest bonds, also known as inverse floating rate securities, which have the economic effect of leverage. If the Fund invests 25% or more of its gross assets in any one state (or U.S. territory) the Fund may be more susceptible to adverse economic, political or regulatory occurrences affecting a particular state (or territory).

The Fund may purchase municipal obligations in the form of bonds, notes, leases or certificates of participation; structured as callable or non-callable; with payment forms that include fixed coupon, variable rate, zero-coupon, capital appreciation bonds, residual interest bonds and short-term floating-rate securities. Such municipal obligations may be acquired through investments in pooled vehicles, partnerships, or other investment companies. No established resale market exists for certain of the municipal obligations in which the Fund may invest. The Fund has no limitation on the amount of its assets that may be invested in securities that are not readily marketable or are subject to restrictions on resale.

In addition to investing in residual interest bonds, the Fund may invest without limitation in other derivative instruments (which are instruments that derive their value from another instrument, security or index) acquired for hedging purposes. The Fund may purchase and sell various kinds of financial futures contracts and related options, including futures contracts and related options based on various debt securities and securities indices. The Fund also may enter into interest rate, total return and other swaps and forward rate contracts to seek to hedge against changes in interest rates or for other risk management purposes.

During unusual market conditions, the Fund may invest up to 100% of its assets in cash or cash equivalents temporarily, which may be inconsistent with its investment objective(s) and other policies.

Principal Risks

Market Discount Risk.

As with any security, the market value of the common shares may increase or decrease from the amount initially paid for the common shares. The Fund’s common shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Fund’s NAV may decrease.

Investment and Market Risk.

An investment in common shares of the Fund is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in common shares represents an indirect investment in the securities owned by the Fund, which will generally trade in the over-the-counter (“OTC”) markets. The common shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions.

See Endnotes and Additional Disclosures in this report.

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Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

The Fund's Investment Objectives, Principal Strategies and Principal Risks

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The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in

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U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of such resulting changes in the value of the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets.

Municipal Obligations Risk

. The amount of public information available about municipal obligations is generally less than for corporate equities or bonds, meaning that the investment performance of municipal obligations may be more dependent on the analytical abilities of the investment adviser than stock or corporate bond investments. The secondary market for municipal obligations also tends to be less well-developed and less liquid than many other securities markets, which may limit the Fund’s ability to sell its municipal obligations at attractive prices. The differences between the price at which an obligation can be purchased and the price at which it can be sold may widen during periods of market distress. Less liquid obligations can become more difficult to value and be subject to erratic price movements. The increased presence of nontraditional participants (such as proprietary trading desks of investment banks and hedge funds) or the absence of traditional participants (such as individuals, insurance companies, banks and life insurance companies) in the municipal markets may lead to greater volatility in the markets because non-traditional participants may trade more frequently or in greater volume.

Interest Rate Risk.

In general, the value of debt instruments will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Duration measures the time-weighted expected cash flows of a fixed-income security, while maturity refers to the amount of time until a fixed-income security matures. Generally, securities with longer durations or maturities are more sensitive to changes in interest rates than securities with shorter durations or maturities, causing them to be more volatile. Conversely, fixed-income securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-income securities with longer durations or maturities. Because the Fund is managed toward an income objective, it may hold more longer-duration or maturity obligations and thereby be more exposed to interest rate risk than municipal income funds that are managed with a greater emphasis on total return. The impact of interest rate changes is significantly less for floating-rate instruments that have relatively short periodic rate resets (e.g., ninety days or less). In a rising interest rate environment, the durations or effective maturities of income securities that have the ability to be prepaid or called by the issuer may be extended. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest rate. Certain instruments held by the Fund were historically based on the London Interbank Offered Rate (“LIBOR”), which was the average offered rate for various maturities of short-term loans between certain major international banks. LIBOR historically was used throughout global banking and financial industries to determine interest rates for a variety of financial instruments (such as debt instruments and derivatives) and borrowing arrangements. Upon a determination by regulators to phase out the use of LIBOR, market participants have been transitioning to the use of alternative reference rates over the past few years. As of June 30, 2023, the administrator of LIBOR ceased publishing LIBOR settings. The impact of the transition away from LIBOR  on certain debt securities, derivatives and other financial instruments that utilize LIBOR remains uncertain. The transition away from  LIBOR and the use of replacement rates may adversely affect transactions that used LIBOR as a reference rate, financial institutions, funds and other market participants that engaged in such transactions, and the financial markets generally.

Credit Risk.

Investments in municipal obligations and other debt obligations (referred to below as “debt instruments”) are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Fund shares and income distributions. The value of debt instruments also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of debt instruments may be lowered if the financial condition of the party obligated to make payments with respect to such instruments deteriorates. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Fund may be required to retain legal or similar counsel, which may increase the Fund’s operating expenses and adversely affect net asset value. Municipal obligations may be insured as to principal and interest payments. If the claims-paying ability or other rating of the insurer is downgraded by a rating agency, the value of such obligations may be negatively affected.

Lower Rated Investments Risk.

Investments rated below investment grade and comparable unrated investments (sometimes referred to as “junk”) are speculative because of increased credit risk relative to other fixed income investments. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and illiquidity than higher rated investments.

Inflation Risk/Deflation Risk.

Inflation risk is the risk that the value of assets or income from investment will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the common shares and distributions thereon can decline. In addition, during periods of rising inflation, short-term interest rates and the Fund’s cost of leverage would likely increase, reducing returns to the common shareholders to the extent that such increased cost is not offset by commensurately higher income. Deflation risk is the risk that prices throughout the economy decline over time − the opposite of inflation. Deflation may have an adverse affect on the creditworthiness of issuers and may make issuer defaults more likely, which may result in a decline in the value of the Fund’s investments.

See Endnotes and Additional Disclosures in this report.

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Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

The Fund's Investment Objectives, Principal Strategies and Principal Risks

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Unrated Securities Risk.

The Fund may invest in unrated obligations for which Eaton Vance will make a credit quality determination for purposes of the Fund’s credit quality policy. To the extent that the Fund invests in such unrated obligations, the Fund’s credit quality will be more dependent on Eaton Vance’s credit analysis than if the Fund invested in only rated obligations. Some unrated securities may not have an active trading market or may be difficult to value.

Leverage Risk.

Certain Fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to an underlying reference instrument. Leverage can also result from borrowings, issuance of preferred shares or participation in residual interest bond transactions. Leverage can increase both the risk and return potential of the Fund. The use of leverage may cause the Fund to maintain liquid assets or liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations. Leverage may cause the Fund’s NAV to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the Fund’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment.

Risk of Residual Interest Bonds.

The Fund may enter into residual interest bond transactions, which expose the Fund to leverage and greater risk than an investment in a fixed-rate municipal bond. The interest payments that the Fund receives on the residual interest bonds acquired in such transactions vary inversely with short-term interest rates, normally decreasing when short-term rates increase. The value and market for residual interest bonds are volatile and such bonds may have limited liquidity. As required by applicable accounting standards, the Fund records interest expense on its liability with respect to floating-rate notes and also records offsetting interest income in an amount equal to this expense.

Call and Reinvestment Risks.

If interest rates fall, it is possible that issuers of callable bonds with high interest coupons will “call” (or prepay) their bonds before their maturity date. If a call were exercised by the issuer during a period of declining interest rates, the Fund would likely replace such called security with a lower yielding security. If that were to happen, it could decrease the Fund’s dividends and possibly could affect the market price of common shares. Similar risks exist when the Fund invests the proceeds from matured or traded municipal obligations at market interest rates that are below the Fund’s current earnings rate.

Municipal Lease Obligations (“MLOs”) and Certificates of Participation.

The Fund may invest in MLOs and certificates of participation involve special risks not normally associated with general obligations or revenue bonds. MLOs are bonds that are secured by lease payments made by the party, typically a state or municipality, leasing the facilities (e.g., schools or office buildings) that were financed by the bond. Interest income from MLOs is generally exempt from local and state taxes in the state of issuance. MLOs, like other municipal debt obligations, are subject to the risk of non-payment. Although MLOs do not constitute general obligations of the issuer for which the issuer’s unlimited taxing power is pledged, the leasing state or municipality may be obligated to appropriate funds from its general tax revenues to make lease payments as long as it utilizes the leased property. Other lease payments may be subject to annual appropriation or may be made only from revenues associated with the facility financed. For example, certain lease obligations contain “non-appropriation” clauses, which provide that the issuer has no obligation to make lease or installment purchase payments in future years unless money is appropriated for such purpose on a yearly basis, which function to render constitutional and statutory requirements for the issuance of debt inapplicable to such obligations. In addition, such leases or contracts may be subject to temporary abatement of payments in the event the governmental issuer is prevented from maintaining occupancy of the leased premises or utilizing the leased equipment. Although “non-appropriation” lease obligations may be secured by the leased property, disposition of the property in the event of foreclosure might prove difficult, time consuming and costly, and may result in a delay in recovering or the failure to fully recover ownership of the assets.

A certificate of participation (also referred to as a “participation”) in a municipal lease is an instrument evidencing a pro rata share in a specific pledged revenue stream, usually lease payments by the issuer that are typically subject to annual appropriation. The certificate generally entitles the holder to receive a share, or participation, in the payments from a particular project. Certificates of participation involve the same risks as the underlying municipal leases. In addition, the Fund may be dependent upon the municipal authority issuing the certificate of participation to exercise remedies with respect to an underlying lease. Certificates of participation also entail a risk of default or bankruptcy, both of the issuer of the municipal lease and also the municipal agency issuing the certificate of participation.

MLOs and participations therein represent a type of financing that may not have the depth of marketability associated with more conventional securities and, as such, they may be less liquid than conventional securities. Certain MLOs may be deemed illiquid, unless determined by the Fund’s investment adviser, pursuant to guidelines adopted by the Board, to be liquid securities. The Fund’s investment adviser will consider the factors it believes are relevant to the marketability of the obligation, to the extent that information regarding such factor is available to the Fund’s investment adviser and pertinent to the liquidity determination, which may include: (1) the willingness of dealers to bid for the obligation; (2) the number of dealers willing to purchase or sell the obligation and the number of other potential buyers; (3) the frequency of trades and quotes for the obligation; (4) the nature of the marketplace trades, including the time needed to dispose of the obligation, the method of soliciting offers, and the mechanics of transfer; (5) the willingness of the governmental issuer to continue to appropriate funds for the payment of the obligation; (6) how likely or remote an event of non-appropriation may be, which depends in varying degrees on a variety of factors, including those relating to the general creditworthiness of the governmental issuer, its dependence on its continuing access to the credit markets, and the importance to the issuer of the equipment, property or facility covered by the lease or contract; (7) an assessment of the likelihood that the lease may or may not be cancelled; and (8) other factors and information unique to the obligation in determining its liquidity.

See Endnotes and Additional Disclosures in this report.

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Eaton Vance

National Municipal Opportunities Trust

March 31, 2024

The Fund's Investment Objectives, Principal Strategies and Principal Risks

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The ability of issuers of MLOs to make timely lease payments may be adversely impacted in general economic downturns and as relative governmental cost burdens are allocated

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reallocated among federal, state and local governmental units. Such non-payment would result in a reduction of income from and value of the obligation. Issuers of MLOs might seek protection under the bankruptcy laws. In the event of bankruptcy of such an issuer, holders of MLOs could experience delays and limitations with respect to the collection of principal and interest on such MLOs and may not, in all circumstances, be able to collect all principal and interest to which it is entitled. To enforce its rights in the event of a default in lease payments, the Fund might take possession of and manage the assets securing the issuer’s obligations on such securities or otherwise incur costs to protect its right, which may increase the Fund’s operating expenses and adversely affect the net asset value of the Fund. When the lease contains a non-appropriation clause, however, the failure to pay would not be a default and the Fund would not have the right to take possession of the assets. Any income derived from the Fund’s ownership or operation of such assets may not be tax-exempt.

Restricted Securities Risk.

Unless registered for sale to the public under applicable federal securities law, restricted securities can be sold only in private transactions to qualified purchasers pursuant to an exemption from registration. The sale price realized from a private transaction could be less than the Fund’s purchase price for the restricted security. It may be difficult to identify a qualified purchaser for a restricted security held by the Fund and such security could be deemed illiquid. It may also be more difficult to value such securities.

Derivatives Risk.

The Fund’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instrument”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in OTC markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment.

Counterparty Risk.

Changes in the credit quality of the companies that serve as the Fund’s counterparties with respect to its derivatives positions and liquidity providers for the Fund’s residual interest bonds or other investments supported by another party’s credit will affect the value of those instruments. Certain entities that have served as counterparties in the municipals markets have recently incurred significant financial hardships, including bankruptcy and material loss of credit standing as a result of exposure to investments that have experienced defaults or otherwise suffered extreme credit deterioration. As a result, such hardships have reduced these entities’ capital and called into question their continued ability to perform their obligations. By using derivatives or other instruments that expose the Fund to counterparties, the Fund assumes the risk that its counterparties could experience future financial hardship.

The counterparty risk for cleared derivatives is generally lower than for uncleared OTC derivative transactions since generally a clearing organization becomes substituted for each counterparty to a cleared derivative contract and, in effect, guarantees the parties’ performance under the contract as each party to a trade looks only to the clearing organization for performance of financial obligations under the derivative contract. However, there can be no assurance that a clearing organization, or its members, will satisfy its obligations to the Fund.

Liquidity Risk.

The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Insurance Risk.

Municipal obligations may be insured as to their scheduled payment of principal and interest. Although the insurance feature may reduce some financial risks, the premiums for insurance and the higher market price sometimes paid for insured obligations may reduce the current yield on the insured obligation. Insured obligations also may be secured by bank credit agreements or escrow accounts. Changes in the ratings of an insurer may affect the value of an insured obligation, and in some cases may even cause the value of a security to be less than a comparable uninsured obligation. The insurance does not guarantee the market value of the insured obligation or the net asset value of the Fund’s shares. The credit rating of an insured obligation reflects the credit rating of the insurer, based on its claims-paying ability. The obligation of a municipal bond insurance company to pay a claim extends over the life of each insured obligation. Although defaults on insured municipal obligations have been low to date and municipal bond insurers have met their claims, there is no assurance this will continue. A higher than expected default rate could strain the insurer’s loss reserves and adversely affect its ability to pay claims to bondholders. Because a significant portion of insured municipal obligations that have been issued and are outstanding is insured by a small number of insurance companies, an event involving one or more of these insurance companies, such as a credit rating downgrade, could have a significant adverse effect on the value of the municipal obligations insured by that insurance company and on the municipal bond markets as a whole.

See Endnotes and Additional Disclosures in this report.

8

Item 2. Code of Ethics

The registrant (sometimes referred to as the “Fund”) has adopted a code of ethics applicable to its Principal Executive Officer, Principal Financial Officer and Principal Accounting Officer. The registrant undertakes to provide a copy of such code of ethics to any person upon request, without charge, by calling 1-800-262-1122. The registrant has not amended the code of ethics as described in Form N-CSR during the period covered by this report. The registrant has not granted any waiver, including an implicit waiver, from a provision of the code of ethics as described in Form N-CSR during the period covered by this report.

Item 3. Audit Committee Financial Expert

The registrant’s Board of Trustees (the “Board”) has designated George J. Gorman and Scott E. Wennerholm, each an independent trustee, as audit committee financial experts. Mr. Gorman is a certified public accountant who is the Principal at George J. Gorman LLC (a consulting firm). Previously, Mr. Gorman served in various capacities at Ernst & Young LLP (a registered public accounting firm), including as Senior Partner. Mr. Gorman also has experience serving as an independent trustee and audit committee financial expert of other

mutual fund complexes. Mr. Wennerholm is a private investor. Previously, Mr. Wennerholm served as a Trustee at Wheelock College (postsecondary institution), as a Consultant at GF Parish Group (executive recruiting firm), Chief Operating Officer and Executive Vice President at BNY Mellon Asset Management (investment management firm), Chief Operating Officer and Chief Financial Officer at Natixis Global Asset Management (investment management firm), and Vice President at Fidelity Investments Institutional Services (investment management firm).

Item 4. Principal Accountant Fees and Services

(a) –(d)

The following table presents the aggregate fees billed to the registrant for the registrant’s fiscal years ended March 31, 2023 and March 31, 2024 by the registrant’s principal accountant, Deloitte & Touche LLP (“D&T”), for professional services rendered for the audit of the registrant’s annual financial statements and fees billed for other services rendered by D&T during such periods.

(e)(1) The registrant’s audit committee has adopted policies and procedures relating to the pre-approval of services provided by the registrant’s principal accountant (the “Pre-Approval Policies”). The Pre-Approval Policies establish a framework intended to assist the audit committee in the proper discharge of its pre-approval responsibilities. As a general matter, the Pre-Approval Policies (i) specify certain types of audit, audit-related, tax, and other services determined to be pre-approved by the audit committee; and (ii) delineate specific procedures governing the mechanics of the pre-approval process, including the approval and monitoring of audit and non-audit service fees. Unless a service is specifically pre-approved under the Pre-Approval Policies, it must be separately pre-approved by the audit committee.

The Pre-Approval Policies and the types of audit and non-audit services pre-approved therein must be reviewed and ratified by the registrant’s audit committee at least annually. The registrant’s audit committee maintains full responsibility for the appointment, compensation, and oversight of the work of the registrant’s principal accountant.

(e)(2) No services described in paragraphs (b)-(d) above were approved by the registrant’s audit committee pursuant to the “de minimis exception” set forth in Rule 2-01 (c)(7)(i)(C) of Regulation S-X.

(f) Not applicable.

(g) The following table presents (i) the aggregate non-audit fees (i.e., fees for audit-related, tax, and other services) billed to the registrant by D&T for the registrant’s fiscal years ended March 31, 2023 and March 31, 2024; and (ii) the aggregate non-audit fees (i.e., fees for audit-related, tax, and other services) billed to the Eaton Vance organization by D&T for the same time periods.

(h) The registrant’s audit committee has considered whether the provision by the registrant’s principal accountant of non-audit services to the registrant’s investment adviser and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant that were not pre-approved pursuant to Rule 2-01(c)(7)(ii) of Regulation S-X is compatible with maintaining the principal accountant’s independence.

(i) Not applicable.

(j) Not applicable.

Item 5. Audit Committee of Listed Registrants

The registrant has a separately-designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Securities and Exchange Act of 1934, as amended. George J. Gorman, Keith Quinton, Scott E. Wennerholm (Chair), and Nancy A. Wiser are the members of the registrant’s audit committee.

Item 6. Schedule of Investments

Please see schedule of investments contained in the Report to Stockholders included under Item 1 of this Form N-CSR.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

The Board of the Fund has adopted a proxy voting policy and procedure (the “Fund Policy”), pursuant to which the trustees have delegated proxy voting responsibility to the Fund’s investment adviser and adopted the investment adviser’s proxy voting policies and procedures (the “Policies”) which are described below. The trustees will review the Policies annually. In the event that a conflict of interest arises between the Fund’s shareholders and the investment adviser, the administrator, or any of their affiliates or any affiliate of the Fund, the investment adviser will generally refrain from voting the proxies related to the companies giving rise to such conflict until it consults with the Board, or any committee, sub-committee or group of independent trustees identified by the Board, which will instruct the investment adviser on the appropriate course of action. If the Board Members are unable to meet and the failure to vote a proxy would have a material adverse impact on the Fund, the investment adviser may vote such proxy, provided that it discloses the existence of the material conflict to the Chairperson of the Fund’s Board as soon as practicable and to the Board at its next meeting.

The Policies are designed to promote accountability of a company’s management to its shareholders and to align the interests of management with those shareholders. An independent proxy voting service (“Agent”), currently Institutional Shareholder Services, Inc., has been retained to assist in the voting of proxies through the provision of vote analysis, implementation and recordkeeping and disclosure services. The investment adviser will generally vote proxies through the Agent. The Agent is required to vote all proxies in accordance with customized proxy voting guidelines (the “Guidelines”) and/or refer them back to the investment adviser pursuant to the Policies.

The Agent is required to establish and maintain adequate internal controls and policies in connection with the provision of proxy voting services, including methods to reasonably ensure that its analysis and recommendations are not influenced by a conflict of interest. The Guidelines include voting guidelines for matters relating to, among other things, the election of directors, approval of independent auditors, executive compensation, corporate structure and anti-takeover defenses. The investment adviser may cause the Fund to abstain from voting from time to time where it determines that the costs associated with voting a proxy outweigh the benefits derived from exercising the right to vote or it is unable to access or access timely ballots or other proxy information, among other stated reasons. The Agent will refer Fund proxies to the investment adviser for instructions under circumstances where, among others: (1) the application of the Guidelines is unclear; (2) a particular proxy question is not covered by the Guidelines; or (3) the Guidelines require input from the investment adviser. When a proxy voting issue has been referred to the investment adviser, the analyst (or portfolio manager if applicable) covering the company subject to the proxy proposal determines the final vote (or decision not to vote) and the investment adviser’s Proxy Administrator (described below) instructs the Agent to vote accordingly for securities held by the Fund. Where more than one analyst covers a particular company and the recommendations of such analysts voting a proposal conflict, the investment adviser’s Global Proxy Group (described below) will review such recommendations and any other available information related to the proposal and determine the manner in which it should be voted, which may result in different recommendations for the Fund that may differ from other clients of the investment adviser.

The investment adviser has appointed a Proxy Administrator to assist in the coordination of the voting of client proxies (including the Fund’s) in accordance with the Guidelines and the Policies. The investment adviser and its affiliates have also established a Global Proxy Group. The Global Proxy Group develops the investment adviser’s positions on all major corporate issues, creates the Guidelines and oversees the proxy voting process. The Proxy Administrator maintains a record of all proxy questions that have been referred by the Agent, all applicable recommendations, analysis and research received and any resolution of the matter. Before instructing the Agent to vote contrary to the Guidelines or the recommendation of the Agent, the Proxy Administrator will provide the Global Proxy Group with the Agent’s recommendation for the proposal along with any other relevant materials, including the basis for the analyst’s recommendation. The Proxy Administrator will then instruct the Agent to vote the proxy in the manner determined by the Global Proxy Group. A similar process will be followed if the Agent has a conflict of interest with respect to a proxy. The investment adviser will report to the Fund’s Board any votes cast contrary to the Guidelines or Agent recommendations, as applicable, no less than annually.

The investment adviser’s Global Proxy Group is responsible for monitoring and resolving possible material conflicts with respect to proxy voting. Because the Guidelines are predetermined and designed to be in the best interests of shareholders, application of the Guidelines to vote client proxies should, in most cases, adequately address any possible conflict of interest. The investment adviser will monitor situations that may result in a conflict of interest between any of its clients and the investment adviser or any of its affiliates by maintaining a list of significant existing and prospective corporate clients. The Proxy Administrator will compare such list with the names of companies of which he or she has been referred a proxy statement (the “Proxy Companies”). If a company on the list is also a Proxy Company, the Proxy Administrator will report that fact to the Global Proxy Group. If the Proxy Administrator intends to instruct the Agent to vote in a manner inconsistent with the Guidelines, the Global Proxy Group will first determine, in consultation with legal counsel if necessary,

whether a material conflict exists. If it is determined that a material conflict exists, the investment adviser will seek instruction on how the proxy should be voted from the Fund’s Board, or any committee or subcommittee identified by the Board. If a matter is referred to the Global Proxy Group, the decision made and basis for the

Information on how the Fund voted proxies relating to portfolio securities during the most recent 12 month period ended June 30 is available (1) without charge, upon request, by calling 1-800-262-1122, and (2) on the Securities and Exchange Commission’s website at http://www.sec.gov.

Item 8. Portfolio Managers of Closed-End Management Investment Companies

Eaton Vance Management (“EVM” or “Eaton Vance”) is the investment adviser of the Fund. Cynthia J. Clemson and William J. Delahunty Jr. are responsible for the overall and day-to-day management of the Fund’s investments.

Ms. Clemson is a Vice President of EVM, is Co-Director of Municipal Investments and has been a portfolio manager of the Fund since May 2009. She has managed other Eaton Vance portfolios for more than five years. Mr. Delahunty is a Vice President of EVM and has been a portfolio of the Fund since October 2021. He has been employed by EVM for more than five years. This information is provided as of the date of filing this report.

The following table shows, as of the Fund’s most recent fiscal year end, the number of accounts each portfolio manager managed in each of the listed categories and the total assets (in millions of dollars) in the accounts managed within each category. The table also shows the number of accounts with respect to which the advisory fee is based on the performance of the account, if any, and the total assets (in millions of dollars) in those accounts.

The following table shows the dollar range of Fund shares beneficially owned by each portfolio manager as of the Fund’s most recent fiscal year end.

Potential for Conflicts of Interest. It is possible that conflicts of interest may arise in connection with a portfolio manager’s management of the Fund’s investments on the one hand and the investments of other accounts for which a portfolio manager is responsible on the other. For example, a portfolio manager may have conflicts of interest in allocating management time, resources and investment opportunities among the Fund and

other accounts he or she advises. In addition, due to differences in the investment strategies or restrictions between the Fund and the other accounts, the portfolio manager may take action with respect to another account that differs from the action taken with respect to the Fund. In some cases, another account managed by a portfolio manager may compensate the investment adviser based on the performance of the securities held by that account. The existence of such a performance based fee may create additional conflicts of interest for the portfolio manager in the allocation of management time, resources and investment opportunities. Whenever conflicts of interest arise, the portfolio manager will endeavor to exercise his or her discretion in a manner that he or she believes is equitable to all interested persons. EVM has adopted several policies and procedures designed to address these potential conflicts including a code of ethics and policies that govern the investment adviser’s trading practices, including among other things the aggregation and allocation of trades among clients, brokerage allocations, cross trades and best execution.

Compensation Structure for EVM

The compensation structure of Eaton Vance and its affiliates that are investment advisers (for purposes of this section “Eaton Vance”) is based on a total reward system of base salary and incentive compensation, which is paid either in the form of cash bonus, or for employees meeting the specified deferred compensation eligibility threshold, partially as a cash bonus and partially as mandatory deferred compensation. Deferred compensation granted to Eaton Vance employees is generally granted as a mix of deferred cash awards under the Investment Management Alignment Plan (IMAP) and equity-based awards in the form of stock units. The portion of incentive compensation granted in the form of a deferred compensation award and the terms of such awards are determined annually by the Compensation, Management Development and Succession Committee of the Board of Directors of Eaton Vance’s parent company, Morgan Stanley.

Base salary compensation. Generally, portfolio managers and research analysts receive base salary compensation based on the level of their position with the adviser.

Incentive compensation. In addition to base compensation, portfolio managers and research analysts may receive discretionary year-end compensation. Incentive compensation may include:

Eaton Vance compensates employees based on principles of pay-for-performance, market competitiveness and risk management. Eligibility for, and the amount of any, discretionary compensation is subject to a multi-dimensional process. Specifically, consideration is given to one or more of the following factors, which can vary by portfolio management team and circumstances:

Further, the firm’s Global Incentive Compensation Discretion Policy requires compensation managers to consider only legitimate, business related factors when exercising discretion in determining variable incentive compensation, including adherence to Morgan Stanley’s core values, conduct, disciplinary actions in the current performance year, risk management and risk outcomes.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

No such purchases this period.

Item 10. Submission of Matters to a Vote of Security Holders

No material changes.

Item 11. Controls and Procedures

(a) It is the conclusion of the registrant’s principal executive officer and principal financial officer that the effectiveness of the registrant’s current disclosure controls and procedures (such disclosure controls and procedures having been evaluated within 90 days of the date of this filing) provide reasonable assurance that the information required to be disclosed by the registrant has been recorded, processed, summarized and reported within the time period specified in the Commission’s rules and forms and that the information required to be disclosed by the registrant has been accumulated and communicated to the registrant’s principal executive officer and principal financial officer in order to allow timely decisions regarding required disclosure.

(b) There have been no changes in the registrant’s internal controls over financial reporting during the second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Disclosure of Securities Lending Activities for Closed-End Management Investment Companies

No activity to report for the registrant’s most recent fiscal year end.

Item 13. Exhibits

Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

EATON VANCE NATIONAL MUNICIPAL OPPORTUNITIES TRUST

FORM N-CSR

Exhibit 13(a)(2)(i)

CERTIFICATION

I, James F. Kirchner, certify that:

1. I have reviewed this report on Form N-CSR of Eaton Vance National Municipal Opportunities Trust;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer(s) and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

EATON VANCE NATIONAL MUNICIPAL OPPORTUNITIES TRUST

FORM N-CSR

Exhibit 13(a)(2)(ii)

CERTIFICATION

I, Kenneth A. Topping, certify that:

1. I have reviewed this report on Form N-CSR of Eaton Vance National Municipal Opportunities Trust;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer(s) and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Form N-CSR Item 13(b) Exhibit

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

The undersigned hereby certify in their capacity as Principal Financial Officer and Principal Executive Officer, respectively, of Eaton Vance National Municipal Opportunities Trust (the “Trust”) that:

A signed original of this written statement required by section 906 has been provided to the Trust and will be retained by the Trust and furnished to the Securities and Exchange Commission or its staff upon request.

Form N-CSR Item 13(d) Exhibit

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement No. 333-265180 on Form N-2 of our report dated May 17, 2024, relating to the financial statements and financial highlights of Eaton Vance National Municipal Opportunities Trust (the “Trust”), appearing in this Annual Report on Form N-CSR of the Trust for the year ended March 31, 2024.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

May 24, 2024