SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of July 2025

Eni S.p.A.

(Exact name of Registrant as specified in its charter)

Piazzale Enrico Mattei 1 - 00144 Rome, Italy

(Address of principal executive offices)

(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 x Form 40-F ¨

(Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2b under the Securities Exchange Act of 1934.)

Yes ¨ No x

(If "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): _____)

Table of contents

SIGNATURES

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, hereunto duly authorised.

Date: July 9, 2025

Eni: report on the purchase of treasury shares during the period from 30 June to 4 July 2025

San Donato Milanese (Milan), 9 July 2025 – During the period from 30 June to 4 July 2025, Eni acquired on the Euronext Milan no. 3,599,998 shares (equal to 0.11% of the share capital), at a weighted average price per share equal to 13.8894 euro, for a total consideration of 50,001,849.83 euro within the treasury shares program approved by the Shareholders' Meeting on 14 May 2025, previously subject to disclosure in accordance with applicable legislation.

On the basis of the information provided by the intermediary appointed to make the purchases, here below a synthesis of transactions for the purchase of treasury shares on the Euronext Milan on a daily basis:

From the start on 20 May 2025 of the buyback program, Eni acquired no. 25,109,648 shares (equal to 0.80% of the share capital) for a total consideration of 340,002,790.56 euro.

Considering the treasury shares already held and the purchases made, Eni holds n. 116,719,975 shares equal to 3.71% of the share capital.

Details of the daily transactions made during the period from 30 June to 4 July 2025 are reported below.