Atlantica Announces Private Offering of Additional $285 Million of 6.375% Green Senior Notes due 2032

November 3, 2025 - Atlantica Sustainable Infrastructure Group plc (“Atlantica Group” or the “Issuer”) and Atlantica Sustainable Infrastructure Ltd (“Atlantica” and together with the Issuer, collectively, the “Co-Issuers”) intend, subject to market and other conditions, to offer and sell (the “Green Notes Offering”) in a private placement to eligible purchasers an additional $285 million in aggregate principal amount of 6.375% Green Senior Notes due 2032 (the “Green Notes”). The Green Notes are being offered as additional Green Senior Notes due 2032 under the Indenture governing the Green Notes, dated November 6, 2024 and will be guaranteed by certain of the Co-Issuers’ subsidiaries.

The Co-Issuers intend to use the net proceeds from the Green Notes Offering to (i) fully or partially repay our existing borrowings under the credit agreement, dated as of November 6, 2024, by and among the Co-Issuers and the other parties named therein, as amended, and pay related premiums, fees and expenses and (ii) fund a concurrently announced tender offer (the “Tender Offer”) for up to $85 million aggregate principal amount of Atlantica’s 4.125% Green Senior Secured Notes due 2028 and pay related fees and expenses. In the event that the Tender Offer is not consummated, or the net proceeds from the Green Notes Offering exceed the amount needed to fund the purchase of securities accepted pursuant to the Tender Offer, the Co-Issuers intend to use such net proceeds for general corporate purposes (which may include other repayment or repurchases of indebtedness).

The Green Notes and related guarantees have not been, and will not be, registered under the Securities Act of 1933, as amended (the “Securities Act”), or any state securities laws and, unless so registered, may not be offered or sold in the United States except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act and the rules promulgated thereunder and applicable state securities laws. The Green Notes will be offered only to persons reasonably believed to be qualified institutional buyers in reliance on Rule 144A under the Securities Act and non-U.S. persons in transactions outside the United States in reliance on Regulation S under the Securities Act.

The information contained herein is not for publication or distribution, directly or indirectly, in any jurisdiction where the distribution of such information is restricted by law, and does not constitute an offer to sell, or a solicitation of an offer to buy securities. No sale of the Green Notes and related guarantees will be made in any state or jurisdiction in which such offer, solicitation or sale would be unlawful under the securities laws of any such state or jurisdiction. Any offers of the Green Notes and related guarantees are being made only by means of a private offering memorandum.

This notice and any other documents or materials relating to the issue of the Green Notes are for distribution within the United Kingdom only to persons who (i) have professional experience in matters relating to investments falling within article 19(5) of the Financial Services and Markets Act 2000 (as amended, the “FSMA”) (Financial Promotion) Order 2005 (as amended, the “Financial Promotion Order”), (ii) are persons falling within article 49(2)(a) to (d) (“high net worth companies, unincorporated associations, etc.”) of the Financial Promotion Order or (iii) are persons to whom an invitation or inducement to engage in investment activity (within the meaning of section 21 of the FSMA) in connection with the issue of the Green Notes may otherwise lawfully be communicated or caused to be communicated (all such persons together being referred to as “Relevant Persons”). This press release and any other documents or materials relating to the issue of the Green Notes are directed only at Relevant Persons and must not be acted on or relied on by persons who are not Relevant Persons. Any investment or investment activity to which this press release and any other documents or materials relating to the issue of the Green Notes and related Guarantees relates is available only to Relevant Persons and will be engaged in only with Relevant Persons.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of United States securities laws. Any statements that express, or involve discussions as to, expectations, beliefs, plans, objectives, assumptions, strategies, future events or performance (often, but not always, through the use of words or phrases such as may result, are expected to, will continue, is anticipated, likely to be, believe, will, could, should, would, estimated, may, plan, potential, future, projection, goals, target, outlook, predict, aim and intend or words of similar meaning) are not statements of historical facts and may be forward looking. Such statements occur throughout this press release and include, but are not limited to, statements relating to the use of proceeds from the offering of the Green Notes, the consummation of the Green Notes Offering and the consummation of the Tender Offer. Forward-looking statements involve estimates, assumptions and uncertainties. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including uncertainties related to market conditions and the completion of the offering on the anticipated terms or at all, the other factors discussed in the private offering memorandum. Any forward-looking statement speaks only as of the date on which such statement is made, and the Co-Issuers undertake no obligation to update any forward-looking statement to reflect events or circumstances, including, but not limited to, unanticipated events, after the date on which such statement is made, unless otherwise required by law. New factors emerge from time to time, and it is not possible for management to predict all of these factors, nor can it assess the impact of each of these factors on the business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained or implied in any forward-looking statement.

About Atlantica

Atlantica Sustainable Infrastructure Ltd. is a sustainable infrastructure company that owns a diversified portfolio of contracted renewable energy, storage, efficient natural gas, electric transmission, and water assets in North America, Europe, and South America (www.atlantica.com).

Chief Financial Officer Leire Perez E ir@atlantica.com

Communication Irene Rodriguez E ir@atlantica.com T +44 20 3807 6709