EMTN. Base Prospectus dated July 2025

FINAL VERSION

Base Prospectus Dated 24 July 2025

(incorporated with limited liability under the laws of the Kingdom of Spain)

(incorporated with limited liability under the laws of the Kingdom of Spain)

Under the Guaranteed Euro Medium Term Note Programme described in this Base Prospectus (the "Programme"), Enagás Financiaciones, S.A.U. (the "Issuer"), subject to compliance with all relevant laws, regulations and directives, may from time to time issue Guaranteed Euro Medium Term Notes (the "Notes"). The aggregate nominal amount of Notes outstanding will not at any time exceed €4,000,000,000 (or the equivalent in other currencies at the date of issue).

The payment of all amounts due in respect of the Notes will be unconditionally and irrevocably guaranteed by Enagás, S.A. ("Enagás" or the "Guarantor"). The obligations of the Guarantor in that respect (the "Guarantee") are contained in the deed of guarantee dated 24 July 2025.

This Base Prospectus has been approved by the Commission de Surveillance du Secteur Financier (the "CSSF"), as competent authority under Regulation (EU) 2017/1129, as amended (the "Prospectus Regulation"). The CSSF only approves this Base Prospectus as meeting the standards of completeness, comprehensibility and consistency imposed by the Prospectus Regulation. Such approval should not be considered as an endorsement of either the Issuer, the Guarantor or the quality of the Notes that are the subject of this Base Prospectus and investors should make their own assessment as to the suitability of investing in the Notes. The CSSF assumes no responsibility as to the economic and financial soundness of the issue of any Notes or the quality or solvency of the Issuer in line with the provisions of article 6(4) of the Luxembourg Act dated 16 July 2019 relating to prospectuses for securities. Application has also been made to the Luxembourg Stock Exchange for the Notes issued under the Programme to be listed on the official list of the Luxembourg Stock Exchange (the "Official List") and to be admitted to trading on the Luxembourg Stock Exchange's regulated market, which is a regulated market for the purposes of Directive 2014/65/EU of the European Parliament and of the Council on markets in financial instruments, as amended ("MiFID II"). References in this Base Prospectus to Notes being "listed" (and all related references) shall mean that such Notes have been listed on the Official List and admitted to trading on the Luxembourg Stock Exchange's regulated market. Unlisted Notes may not be issued pursuant to the Programme. The relevant Final Terms in respect of the issue of any Notes will specify whether or not such Notes will be listed on the Official List and admitted to trading on the Luxembourg Stock Exchange's regulated market (or any other stock exchange).

Each Series (as defined in "General Description of the Programme - Method of Issue") of Notes will be represented on issue by a temporary global note (each a "temporary Global Note") or a permanent global note (each a "permanent Global Note"). If the Global Note are stated in the applicable Final Terms to be issued in new global note ("NGN") form, the Global Notes will be delivered on or prior to the original issue date of the relevant Tranche to a common Safekeeper (the "Common Safekeeper") for Euroclear Bank SA/NV ("Euroclear") and Clearstream Banking, SA ("Clearstream, Luxembourg"). Global Notes which are not issued in NGN form ("Classic Global Notes" or "CGNs") will be deposited on the issue date of the relevant Tranche with a common depositary on behalf of Euroclear and Clearstream, Luxembourg (the "Common Depositary"). The provisions governing the exchange of interests in Global Notes for other Global Notes and definitive Notes are described in "Summary of Provisions Relating to the Notes while in Global Form".

PRIIPs / IMPORTANT - EEA RETAIL INVESTORS - The Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the European Economic Area ("EEA"). For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client as defined in point (11) of Article 4(1) of MiFID II; or (ii) a customer within the meaning of Directive (EU) 2016/97, where that customer would not qualify as a professional client as defined in point (10) of Article 4(1) of MiFID II. Consequently, no key information document required by Regulation (EU) No 1286/2014 (as amended, the "EU PRIIPs Regulation") for offering or selling the Notes or otherwise making them available to retail investors in the EEA will be prepared and therefore offering or selling the Notes or otherwise making them available to any retail investor in the EEA may be unlawful under the EU PRIIPs Regulation.

MiFID II product governance / target market - The Final Terms in respect of any Notes may include a legend entitled "MiFID II Product Governance" which will outline the target market assessment in respect of the Notes and which channels for distribution of the Notes are appropriate. Any person subsequently offering, selling or recommending the Notes (a "distributor") should take into consideration the target market assessment; however, a distributor subject to MiFID II is responsible for undertaking its own target market assessment in respect of the Notes (by either adopting or refining the target market assessment) and determining appropriate distribution channels.

A determination will be made in relation to each issue about whether, for the purpose of the MiFID II Product Governance rules under EU Delegated Directive 2017/593, as amended (the "MiFID II Product Governance Rules"), any Dealer subscribing for any Notes is a manufacturer in respect of such Notes, but otherwise neither the Arranger nor the Dealers nor any of their respective affiliates will be a manufacturer for the purpose of the MiFID II Product Governance Rules.

PRIIPS / IMPORTANT - UK RETAIL INVESTORS - The Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the United Kingdom ("UK"). For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client, as defined in point (8) of Article 2 of Regulation (EU) No. 2017/565 as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 ("EUWA"); or (ii) a customer within the meaning of the provisions of the Financial Services and Markets Act 2000, as amended (the "FSMA") and any rules or regulations made under the FSMA to implement Directive (EU) 2016/97, where that customer would not qualify as a professional

client, as defined in point (8) of Article 2(1) of Regulation (EU) No. 600/2014 as it forms part of UK domestic law by virtue of the EUWA. Consequently no key information document required by the EU PRIIPs Regulation as it forms part of UK domestic law by virtue of the EUWA (the "UK PRIIPs Regulation") for offering or selling the Notes or otherwise making them available to retail investors in the UK has been prepared and therefore offering or selling the Notes or otherwise making them available to any retail investor in the UK may be unlawful under the UK PRIIPs Regulation.

UK MiFIR product governance / target market - The Final Terms in respect of any Notes may include a legend entitled "UK MiFIR Product Governance" which will outline the target market assessment in respect of the Notes and which channels for distribution of the Notes are appropriate. Any person subsequently offering, selling or recommending the Notes (a "distributor") should take into consideration the target market assessment; however, a distributor subject to the FCA Handbook Product Intervention and Product Governance Sourcebook (the "UK MiFIR Product Governance Rules") is responsible for undertaking its own target market assessment in respect of the Notes (by either adopting or refining the target market assessment) and determining appropriate distribution channels.

A determination will be made in relation to each issue about whether, for the purpose of the UK MiFIR Product Governance Rules, any Dealer subscribing for any Notes is a manufacturer in respect of such Notes, but otherwise neither the Arranger nor the Dealers nor any of their respective affiliates will be a manufacturer for the purpose of the UK MiFIR Product Governance Rules.

Amounts payable on Floating Rate Notes may be calculated by reference to one of the certain reference rates as specified in the relevant Final Terms, as the Euro Interbank Offered Rate ("EURIBOR") which is administered by the European Money Markets Institute ("EMMI") or the Sterling Overnight Index Average ("SONIA") which is administered by the Bank of England. If any such reference rate constitutes a benchmark for the purposes of Regulation (EU) No. 2016/1011, as amended (the "EU Benchmark Regulation"), the relevant Final Terms will indicate whether or not the benchmark is provided by an administrator included in the register of administrators and benchmarks established and maintained by the European Securities and Markets Authority ("ESMA") pursuant to Article 36 of the EU Benchmark Regulation. As at the date of this Base Prospectus, EMMI (the administrator of EURIBOR) appears on the register of administrators and benchmarks established and maintained by ESMA. As at the date of this Base Prospectus, the Bank of England (the administrator of SONIA) does not appear on the register of administrators and benchmarks established and maintained by ESMA pursuant to Article 36 of the EU Benchmark Regulation. As far as the Issuer is aware, the administrator of SONIA does not fall within the scope of the EU Benchmark Regulation by virtue of Article 2 of the EU Benchmark Regulation. The registration status of any administrator under the EU Benchmark Regulation is a matter of public record and, save where required by applicable law, the Issuer does not intend to update the relevant Final Terms to reflect any change in the registration status of the administrator.

The rating of certain Series of Notes to be issued under the Programme may be specified in the relevant Final Terms. Whether or not each credit rating applied for in relation to the relevant Series of Notes will be treated as having been (i) issued or endorsed by a credit rating agency established in the European Union and registered under Regulation (EC) No. 1060/2009, as amended (the "EU CRA Regulation") and/or (ii) issued or endorsed by a credit rating agency established in the United Kingdom and registered or certified under the Regulation (EU) No 1060/2009 as it forms part of the domestic law of the United Kingdom by virtue of the EUWA (the "UK CRA Regulation") will be disclosed in the relevant Final Terms. A list of registered credit rating agencies is published at the European Securities and Market Authority's website: www.esma.europa.eu. The Guarantor's (i) long-term default rating is "BBB+" by Fitch Ratings Ireland Spanish Branch ("Fitch"); (ii) senior unsecured debt rating is A- by Fitch; and (iii) long-term debt rating is "BBB+" by S&P Global Ratings Europe Limited ("S&P"). Fitch and S&P are each a credit rating agency established in the EEA and registered under the EU CRA Regulation.

Prospective investors should have regard to the factors described under the section headed "Risk Factors" in this Base Prospectus.

This Base Prospectus will be valid as a base prospectus under the Prospectus Regulation for 12 months until 24 July 2026. The obligation to supplement this Base Prospectus in the event of significant new factors, material mistakes or material inaccuracies will not apply following the expiry of that period.

This Base Prospectus comprises a base prospectus for Article 8(1) of the Prospectus Regulation.

The Issuer and the Guarantor (the "Responsible Persons") accept responsibility for the information contained in this Base Prospectus. To the best of the knowledge of the Issuer and the Guarantor the information contained in this Base Prospectus is in accordance with the facts. The Base Prospectus as completed by the Final Terms makes no omission likely to affect the import of such information.

This Base Prospectus is to be read in conjunction with all documents which are incorporated herein by reference (see "Documents Incorporated by Reference").

No person has been authorised to give any information or to make any representation other than those contained in this Base Prospectus in connection with the issue or sale of the Notes and, if given or made, such information or representation must not be relied upon as having been authorised by the Issuer, the Guarantor or any of the Dealers or the Arranger (as defined in "General Description of the Programme"). Neither the delivery of this Base Prospectus nor any sale made in connection herewith shall, under any circumstances, create any implication that there has been no change in the affairs of the Issuer or the Guarantor since the date hereof or the date upon which this Base Prospectus has been most recently supplemented or that there has been no adverse change in the financial position of the Issuer or the Guarantor since the date hereof or the date upon which this Base Prospectus has been most recently supplemented or that any other information supplied in connection with the Programme is correct as of any time subsequent to the date on which it is supplied or, if different, the date indicated in the document containing the same.

In the case of any Notes which are to be admitted to trading on a regulated market within the EEA or offered to the public in a Member State of the EEA in circumstances which require the publication of a prospectus under the Prospectus Regulation, the minimum specified denomination shall be €100,000 (or its equivalent in any other currency as at the date of issue of the Notes). Unless otherwise permitted by the current laws and regulations, Notes (including Notes denominated in sterling) which have a maturity of less than one year and in respect of which the issue proceeds are to be accepted by the Issuer in the UK or whose issue otherwise constitutes a contravention of section 19 of FSMA will have a minimum denomination of £100,000 (or its equivalent in other currencies).

The distribution of this Base Prospectus and the offering or sale of the Notes in certain jurisdictions may be restricted by law. Persons into whose possession this Base Prospectus comes are required by the Issuer, the Guarantor, the Dealers and the Arranger to inform themselves about and to observe any such restriction. The Notes and the Guarantee have not been and will not be registered under the U.S. Securities Act of 1933 (the "Securities Act") and the Notes are subject to U.S. tax law requirements. Subject to certain exceptions, Notes may not be offered, sold or delivered within the United States or to, or for the account or benefit of, U.S. persons. For a description of certain restrictions on offers and sales of Notes and on distribution of this Base Prospectus, see "Subscription and Sale".

This Base Prospectus does not constitute an offer of, or an invitation by or on behalf of the Issuer, the Guarantor or the Dealers to subscribe for, or purchase, any Notes.

Each potential investor in any Notes must determine the suitability of that investment in light of its own circumstances. In particular, each potential investor should:

1. have sufficient knowledge and experience to make a meaningful evaluation of the relevant Notes, the merits and risks of investing in the relevant Notes and the information contained or incorporated by reference in this Base Prospectus or any applicable supplement;

2. have access to, and knowledge of, appropriate analytical tools to evaluate, in the context of its particular financial situation, an investment in the relevant Notes and the impact such investment will have on its overall investment portfolio;

3. have sufficient financial resources and liquidity to bear all of the risks of an investment in the relevant Notes, including where principal or interest is payable in one or more currencies, or where the currency for principal or interest payments is different from the potential investor's currency;

4. understand thoroughly the terms of the relevant Notes and be familiar with the behaviour of any relevant indices and financial markets; and

5. be able to evaluate (either alone or with the help of a financial adviser) possible scenarios for economic, interest rate and other factors that may affect its investment and its ability to bear the applicable risks.

Some Notes are complex financial instruments and such instruments may be purchased as a way to reduce risk or enhance yield with an understood, measured, appropriate addition of risk to their overall portfolios. A potential investor should not invest in Notes which are complex financial instruments unless it has the expertise (either alone or with the help of a financial adviser) to evaluate how the Notes will perform under changing conditions, the resulting effects on the value of such Notes and the impact this investment will have on the potential investor's overall investment portfolio.

The Arranger and the Dealers have not separately verified the information contained in this Base Prospectus. None of the Dealers or the Arranger makes any representation, express or implied, or accepts any responsibility, with respect to the accuracy or completeness of any of the information in this Base Prospectus. No Dealer accepts any liability in relation to the information contained or incorporated by reference in this Base Prospectus or any other information provided by the Issuer in connection with the Programme.

To the fullest extent permitted by law, none of the Dealers or the Arranger or the Fiscal Agent accepts any responsibility for the contents of this Base Prospectus or for any other statement, made or purported to be made by the Arranger or a Dealer or the Fiscal Agent or on its behalf in connection with the Issuer, the Guarantor or the issue and offering of the Notes. The Arranger and each Dealer and the Fiscal Agent accordingly disclaims all and any liability whether arising in tort or contract or otherwise (save as referred to above) which it might otherwise have in respect of this Base Prospectus or any such statement. Neither this Base Prospectus nor any other financial statements are intended to provide the basis of any credit or other evaluation and should not be considered as a recommendation by any of the Issuer, the Guarantor, the Arranger or the Dealers that any recipient of this Base Prospectus or any other financial statements should purchase the Notes. Each potential purchaser of Notes should determine for itself the relevance of the information contained in this Base Prospectus and its purchase of Notes should be based upon such investigation as it deems necessary. None of the Dealers or the Arranger undertakes to review the financial condition or affairs of the Issuer or the Guarantor during the life of the arrangements contemplated by this Base Prospectus or to advise any investor or potential investor in the Notes of any information coming to the attention of any of the Dealers or the Arranger.

In connection with the issue of any Tranche (as defined in "General Description of the Programme - Method of Issue"), the Dealer or Dealers (if any) named as the stabilisation manager(s) (the "Stabilisation Manager(s)") (or any person acting on behalf of any Stabilisation Manager(s)) in the applicable Final Terms may over-allot Notes or effect transactions with a view to supporting the market price of the Notes at a level higher than that which might otherwise prevail. However, stabilisation may not necessarily occur. Any stabilisation action may begin on or after the date on which adequate public disclosure of the terms of the offer of the relevant Tranche is made and, if begun, may cease at any time, but it must end no later than the earlier of 30 days after the issue date of the relevant Tranche and 60 days after the date of the allotment of the relevant Tranche. Any stabilisation action or

over-allotment must be conducted by the relevant Stabilisation Manager(s) (or any person acting on behalf of any Stabilisation Manager(s)) in accordance with all applicable laws and rules.

In this Base Prospectus, unless otherwise specified or the context otherwise requires, references to euro and € are to the currency introduced at the start of the third stage of European economic and monetary union pursuant to the Treaty establishing the European Community, as amended; references to $, U.S. dollars or dollars are to United States dollars; and references to "Renminbi" and "CNY" are to the lawful currency of the People's Republic of China (the "PRC", for the purpose of this Base Prospectus only, not including the Hong Kong and Macau Special Administrative Regions or Taiwan).