UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of: June, 2026.

Commission File Number: 001-39789

Fusion Fuel Green PLC

(Translation of registrant’s name into English)

9 Pembroke Street Upper

Dublin D02 KR83

Ireland

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

On June 4, 2026, Fusion Fuel Green PLC, an Irish public limited company (the “Company”), issued a press release relating to a press release dated June 2, 2026 by Jaguar Uranium Corp., a company incorporated under the laws of British Columbia, Canada (“Jaguar”), in connection with an exploration program at the Huemul Uranium-Copper-Vanadium Project (the “Huemul Project”) in the Province of Mendoza, Argentina, a project in which Royal Uranium Inc., a company incorporated under the laws of British Columbia, Canada (“Royal Uranium”), is believed to hold a 1.0% net smelter return (“NSR”) royalty interest. A copy of the press release is furnished as Exhibit 99.1 to this Report on Form 6-K. As previously disclosed in a Report on Form 6-K/A furnished with the U.S. Securities and Exchange Commission (the “SEC”) on February 18, 2026, the Company entered into a Share Exchange Agreement (the “Share Exchange Agreement”), dated as of February 18, 2026, among the Company and certain shareholders of Royal Uranium, pursuant to which the Company will acquire up to 100% of the issued and outstanding shares in the capital of Royal Uranium. The closing of the transactions contemplated under the Share Exchange Agreement remains subject to the satisfaction of certain closing conditions.

The press release attached as Exhibit 99.1 hereto references certain statements, observations, and data reported by Jaguar in its press release dated June 2, 2026. All such statements, observations, and data are solely those of Jaguar and are not made by, adopted by, or attributable to the Company in any manner. The Company has not independently verified any of the information reported by Jaguar and makes no representation or warranty, express or implied, as to the accuracy, completeness, or reliability of such information. Investors should not rely on any statement made by Jaguar as having been made or endorsed by the Company.

Forward-Looking Statements

The press release attached as Exhibit 99.1 hereto and the statements contained therein include “forward-looking statements” within the meaning of Section 27A of the U.S. Securities Act of 1933, as amended, and Section 21E of the U.S. Securities Exchange Act of 1934, as amended, which statements involve substantial risks and uncertainties. Forward-looking statements generally relate to future events or the Company’s future financial or operating performance. In some cases, you can identify these statements because they contain words such as “may,” “will,” “believes,” “expects,” “anticipates,” “estimates,” “projects,” “intends,” “should,” “seeks,” “future,” “continue,” “plan,” “target,” “predict,” “potential,” or the negative of such terms, or other comparable terminology that concern the Company’s expectations, strategy, plans, or intentions. Forward-looking statements relating to expectations about future results or events are based upon information available to the Company as of today’s date and are not guarantees of the future performance of the Company, and actual results may vary materially from the results and expectations discussed. Such forward-looking statements include, but are not limited to, statements regarding the scope, timing and results of Jaguar’s planned exploration activities at the Huemul Project, including the pending assay results from the 200-sample rock sampling program; interpretation and significance of visual field observations and their consistency with historical records; the potential extent, continuity, and economic significance of observed mineralization, including the potential 4-kilometer copper trend at the Uryco zone area of the Huemul Project; the continuing relevance of the historical significance and the exploration potential of the Huemul Project and surrounding district; the anticipated phases and objectives of Jaguar’s exploration plans; the Company’s expected completion of the planned acquisition of a controlling interest in Royal Uranium pursuant to the Share Exchange Agreement and the expected benefits thereof, including the Company’s expectation to gain capital-efficient royalty exposure to potential future production at the Huemul Project; the Company’s expectation to receive a percentage of revenue from any future mineral production at the Huemul Project under the NSR royalty structure, net of certain deductions, without bearing direct exploration, development, or operating costs; statements regarding the supportive policy backdrop for the Huemul Project, including the U.S.-Argentina Critical Minerals Framework and Jaguar’s 2026 collaboration agreement with the Province of Mendoza; statements regarding the strategic importance of the Huemul Project as a royalty asset within Royal Uranium’s portfolio; and the Company’s strategy to establish a diversified energy commodity royalty platform with exposure to critical energy resources. The Company’s expectations and beliefs regarding these matters may not materialize, and actual results in future periods are subject to risks and uncertainties that could cause actual results to differ materially from those projected, including, without limitation: the risk that assay results from Jaguar’s 200-sample rock sampling program may not confirm preliminary visual field observations or may indicate grades, continuity, or mineralization characteristics materially different from those suggested by historical records; the preliminary and qualitative nature of visual field observations, which do not establish the presence of mineralization of economic grade or continuity; the risk that mineralization observed at surface may not be continuous, may not extend to depth, or may not be of sufficient grade or tonnage to support economic extraction; the availability, accuracy, and completeness of historical data, including historical head grades, which have not been independently verified by Jaguar and should not be treated as current mineral resources or mineral reserves; the outcome of environmental and regulatory review processes; the availability of qualified personnel, contractors and equipment; access to exploration sites; political, legal and regulatory conditions in Argentina and the United States; market conditions and commodity prices, including volatility in uranium and natural gas commodity prices, which directly affect the potential value of NSR and other royalty interests; the availability of financing on acceptable terms; other risks described under “Risk Factors” in Jaguar’s Registration Statement on Form S-1 (File No. 333-292006), as amended, and in subsequent filings with the SEC; the ability of the parties to the Share Exchange Agreement to complete the transaction, the Company’s ability to integrate Royal Uranium’s assets into its business, the ability of the parties to obtain any required consents and approvals in connection with the transaction, including the approval of the Company’s shareholders, and to meet all other closing conditions; the realization of revenues from the assets of Royal Uranium, including its royalties, which may depend on, among other things, the commercial development of uranium, the receipt and maintenance of exploration, mining, and environmental permits and approvals by the operators of the underlying properties, regulatory approval, and market demand for uranium; volatility in uranium commodity prices, which directly affect the potential value of NSR and other royalty interests; the risk that operators of royalty-bearing properties may delay, suspend, or abandon exploration or development activities due to insufficient funding, unfavorable economic conditions, technical challenges, or regulatory obstacles; the possibility that exploration activities, including those authorized under recently obtained permits, may not result in the discovery of commercially viable mineral deposits or hydrocarbon reserves; the dependence of the Company on third-party operators over whom it has no operational control, including decisions regarding the pace, scope, and method of exploration and development; the risk that changes in mining, environmental, or energy laws and regulations in the jurisdictions where the royalty assets are located, including Argentina, may adversely affect the feasibility or economics of the underlying projects; political, economic, and social risks associated with operating in foreign jurisdictions, including currency controls, expropriation, nationalization, and changes in fiscal regimes; the risk that royalty agreements may be subject to disputes regarding their scope, enforceability, or the calculation of permitted deductions from gross revenues; competition from existing or new offerings that may emerge; impacts from strategic changes to the Company’s business on net sales, revenues, income from continuing operations, or other results of operations; the Company’s ability to obtain sufficient funding to maintain operations and develop additional services and offerings; and the risks and uncertainties described under Item 3. “Key Information – D. Risk Factors” and elsewhere in the Company’s Annual Report on Form 20-F filed with the SEC on May 9, 2025, and other filings with the SEC. Should any of these risks or uncertainties materialize or should the underlying assumptions about the Company’s business and the commercial markets in which the Company operates prove incorrect, actual results may vary materially from those described as anticipated, estimated or expected. All subsequent written and oral forward-looking statements concerning the Company or other matters and attributable to the Company or any person acting on its behalf are expressly qualified in their entirety by the cautionary statements above. The Company does not undertake any obligation to publicly update any of these forward-looking statements to reflect events or circumstances that may arise after the date hereof, except as required by law.

SIGNATURE

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

ATTACHMENTS / EXHIBITS

EX-99.1