Tenaris S.A.

Share Issue/Capital Change • Oct 24, 2023

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

Tenaris announces new central securities depository and ISIN code

Luxembourg, October 23, 2023. - Tenaris S.A. (NYSE and Mexico: TS and EXM Italy: TEN) ("Tenaris") announced a change from a global depository structure to LuxCSD S.A. ("LuxCSD") as issuer central securities depository ("CSD"), and the appointment of Banque Internationale à Luxembourg S.A. ("BIL"), as LuxCSD principal agent (replacing BNP as common depositary) from October 31, 2023. BIL will also continue to act as Tenaris's paying agent and registrar for its registered shares.

Consequently, the shares' ISIN code will change as follows:

Current ISIN code: LU0156801721 Last trading day with current ISIN code: October 30, 2023

New ISIN code: LU2598331598 First trading day with new ISIN code: October 31, 2023

On October 31, 2023, each share with the current ISIN will be exchanged against one share with the new ISIN.

Neither the change of issuer CSD nor the change in the ISIN code will have any impact on the listing terms or the rights attached to Tenaris's shares or ADRs.

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