FORM 6 - K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a - 16 or 15d - 16 of

the Securities Exchange Act of 1934

As of July 25, 2025

TENARIS, S.A.

(Translation of Registrant's name into English)

26, Boulevard Royal, 4th floor

L-2449 Luxembourg

(Address of principal executive offices)

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

Form 20-F  ✓  Form 40-F      

The attached material is being furnished to the Securities and ExchangeCommission pursuant to Rule 13a-16 and Form 6-K under the Securities Exchange Act of 1934, as amended. This report contains Tenaris’sWeekly Report (July 21, 2025 – July 25, 2025) on the First Tranche of Tenaris Share Buyback Program.

SIGNATURE

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

Date: July 25, 2025

Tenaris, S.A.

By: /s/ Giovanni Sardagna

Giovanni Sardagna

Investor Relations Officer

Giovanni Sardagna

Tenaris

1-888-300-5432

www.tenaris.com

Weekly Report (July 21,2025 – July 25, 2025) on the First Tranche of Tenaris Share Buyback Program.

Luxembourg, July 25, 2025. - Tenaris S.A. (NYSE and Mexico: TS andEXM Italy: TEN) (“Tenaris”) announced today that pursuant to its First Tranche of the USD1.2 billion Share Buyback Programannounced on June 6, 2025, covering up to USD 600 million to be executed in the open market, it has repurchased the following ordinaryshares from July 21, 2025 to (and including) July 25, 2025:

From July 21, 2025 to (and including) July 25, 2025, the Company has purchaseda total of 969,964 ordinary shares for a total consideration of €15,581,391, equivalent to USD18,262,323.

As of July 25, 2025, the Company held in treasury 21,028,303 ordinary sharesequal to 1.96% of the total issued share capital.

Tenaris intends to cancel treasury shares purchased under thePrograms in due course.

Details of the above transactions, are available on Tenaris’s corporate website underthe Share Buyback Program Section https://ir.tenaris.com/share-buyback-program.

Some of the statements contained in this press release are “forward-lookingstatements”. Forward-looking statements are based on management’s current views and assumptions and involve known and unknownrisks that could cause actual results, performance or events to differ materially from those expressed or implied by those statements.These risks include but are not limited to risks arising from uncertainties as to future oil and gas prices and their impact on investmentprograms by oil and gas companies.

Tenaris is a leading global supplier of steel tubes and related servicesfor the world’s energy industry and certain other industrial applications.