Tenaris S.A.

Transaction in Own Shares • Sep 5, 2025

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

Weekly Report (September 1, 2025 – September 5, 2025) on the First Tranche of Tenaris Share Buyback Program.

Luxembourg, September 5, 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 1, 2025 to (and including) September 5, 2025:

Date	Trading Venue	Shares Purchased	Weighted Average Price (EUR)	Purchases in EUR	Reference F X	Purchases in USD
01-sep-25	MTAA	70,000	15.4410	1,080,870	1.1711	1,265,807
02-sep-25	MTAA	50,000	15.4816	774,080	1.1665	902,964
03-sep-25	MTAA	50,000	15.2562	762,810	1.1663	889,665
04-sep-25	MTAA	53,000	15.2434	807,900	1.1635	939,992
05-sep-25	MTAA	100,000	14.9837	1,498,370	1.1734	1,758,187
		323,000	15.2447	4,924,030		5,756,616

From September 1, 2025 to (and including) September 5, 2025, the Company has purchased a total of 323,000 ordinary shares for a total consideration of €4,924,030, equivalent to USD5,756,616.

As of September 5, 2025, the Company held in treasury 29,294,193 ordinary shares equal to 2.73% 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.