Tenaris S.A.

Transaction in Own Shares • Sep 13, 2025

Giovanni Sardagna Tenaris 1-888-300-5432 www.tenaris.com

Weekly Report (September 8, 2025 – September 12, 2025) on the First Tranche of Tenaris Share Buyback Program.

Luxembourg, September 12, 2025. - Tenaris S.A. (NYSE and Mexico: TS and EXM Italy: TEN) ("Tenaris") announced today that pursuant to its First Tranche of the USD1.2 billion Share Buyback Program announced on June 6, 2025, covering up to USD600 million to be executed in the open market, it has repurchased the following ordinary shares from September 8, 2025 to (and including) September 12, 2025:

Date	Trading Venue	Shares Purchased	Weighted Average Price (EUR)	Purchases in EUR	Reference F X	Purchases in USD
08-sep-25	MTAA	50,005	14.9925	749,700	1.1744	880,448
09-sep-25	MTAA	50,000	15.1268	756,340	1.1730	887,187
10-sep-25	MTAA	50,000	15.0599	752,995	1.1726	882,962
11-sep-25	MTAA	50,000	15.3535	767,675	1.1728	900,329
12-sep-25	MTAA	5,000	15.4307	77,154	1.1726	90,466
		205,005	15.1404	3,103,863		3,641,392

From September 8, 2025 to (and including) September 12, 2025, the Company has purchased a total of 205,005 ordinary shares for a total consideration of €3,103,863, equivalent to USD3,641,392.

As of September 12, 2025, the Company held in treasury 29,499,198 ordinary shares equal to 2.75% of the total issued share capital.

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

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

Some of the statements contained in this press release are "forward-looking statements". Forward-looking statements are based on management's current views and assumptions and involve known and unknown risks 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 investment programs by oil and gas companies.

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