Company: TNRSF
Filing Date: 2025-10-01
Form Type: 6-K
Source: 0001171843-25-006202
Chunk: 0

Company: TENARIS SA
Filing Date: 2025-10-01
Form: 6-K
Chunk 0
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<div align='center'>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</div>

As of September 30, 2025

<div align='center'>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 registrant
files or will file annual reports under cover Form 20-F or 40-F.

Form 20-F Form 40-F</div>

The attached material is being furnished to the Securities and Exchange
Commission pursuant to Rule 13a-16 and Form 6-K under the Securities Exchange Act of 1934, as amended. This report contains Tenaris’s
Press Release announcing Tenaris completes USD600 million First Tranche of its Share Buyback Program.

<div align='center'>SIGNATURE</div>

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, thereunto duly authorized.

Date: September 30, 2025

<div align='center'>Tenaris, S.A.</div>

By: /s/ Giovanni Sardagna

Giovanni Sardagna

Investor Relations Officer

Giovanni Sardagna

Tenaris

1-888-300-5432

www.tenaris.com

Tenaris completes USD600 million First Tranche of its Share Buyback Program.

Luxembourg, September 30, 2025. - Tenaris S.A. (NYSE and Mexico:
TS and EXM Italy: TEN) (“Tenaris”) announced today the completion of the first USD600 million tranche of its USD1.2 billion
Share Buyback Program announced on June 6, 2025 (the “Program”).

During this first tranche, which ran from June 9, 2025, to (and including) September 30, 2025,
the Company purchased a total of 33,059,955 ordinary shares, representing 3.08% of its total issued share capital, for a total consideration
of €516,588,880, or approximately USD600 million