Tenaris S A : Notice to the Annual General Meeting of Shareholders

Tenaris S.A.

Société Anonyme

26, Boulevard Royal, 4th Floor,

L-2449 Luxembourg

RCS Luxembourg B 85 203

NOTICE OF THE ANNUAL GENERAL MEETING OF SHAREHOLDERS

TO BE HELD ON 3rd MAY 2021

Notice is hereby given to holders of ordinary shares of Tenaris S.A. (the "Company") that the Annual General Meeting of Shareholders of the Company will be held on 3rd May 2021, at 15:30 (Central European time) (the "Meeting").

At the Meeting, shareholders will vote on the items listed below under the heading "Agenda for the Annual General Meeting of Shareholders."

Agenda for the Annual General Meeting of Shareholders

1. Consideration of the consolidated management report and related management certifications on the Company's consolidated financial statements as of and for the year ended 31st December 2020, and on the annual accounts as at 31st December 2020, and of the external auditors' reports on such consolidated financial statements and annual accounts.
2. Approval of the Company's consolidated financial statements as of and for the year ended 31st December 2020.
3. Approval of the Company's annual accounts as at 31st December 2020.
4. Allocation of results and approval of dividend payment for the year ended 31st December 2020.
5. Discharge of the members of the Board of Directors for the exercise of their mandate throughout the year ended 31st December 2020.
6. Election of the members of the Board of Directors.
7. Approval of the compensation payable to the members of the Board of Directors for the year ending 31st December 2021.
8. Approval of the Company's compensation report for the year ended 31st December 2020.
9. Appointment of the external auditors for the fiscal year ending 31st December 2021, and approval of their fees.
10. Authorization to the Board of Directors to cause the distribution of all shareholder communications, including its shareholder meeting and proxy materials and annual reports to shareholders, by such electronic means as is permitted by any applicable laws or regulations.

Resolutions at the Meeting will be passed by the simple majority of the votes validly cast, irrespective of the number of shares present or represented.

Holders of Shares: procedures for voting at the Meeting

Due to the COVID-19 pandemic, the disease caused by the SARS-CoV-2 virus, on 18th March 2020, the Luxembourg government declared a state of emergency for a period of three months

and enacted, by way of decree, a number of temporary measures on the holding of meetings in companies and other legal entities. Among other measures, companies have been allowed, notwithstanding any provision to the contrary in their articles of association and regardless of the expected number of participants, to hold general meetings of shareholders without a physical meeting and have also been allowed to require shareholders (or other participants in the meeting), subject to certain conditions, to exercise rights exclusively through a proxy holder designated by the company. Subsequently, a series of laws, including the most recent Law of 25th November 2020, extended the application of such measures until 30th June 2021.

In accordance with applicable laws and regulation, for safety reasons, the Company has resolved that shareholders may not attend the Meeting in person and shall, instead, exercise their rights in connection with the Meeting in the manner described in this Notice.

In accordance with the Luxembourg Law of 24th May 2011 (as amended by the Luxemburg Law of 1st August 2019) on the exercise of certain rights of shareholders in general meetings of listed companies (the "Shareholders' Rights Law"), the right to vote at the Meeting is restricted to those shareholders who are holders of shares of the Company on 19th April 2021 at 24:00 (midnight), Central European Time (the "Shareholders' Record Time").

Shareholders will be entitled to exercise their rights in connection with the Meeting exclusively through a proxy holder designated by the Company. No shareholder may attend the Meeting in person. A shareholder will be entitled to vote by proxy at the Meeting in respect of those shares of the Company which such shareholder duly evidences to hold at the Shareholders' Record Time. Any changes to a shareholder's holding of shares after the Shareholders' Record Time shall be disregarded for purposes of determining the right of such shareholder to vote by proxy at the Meeting.

If you are a holder of shares of the Company on the Shareholders' Record Time and you wish to vote by proxy at the Meeting, you must complete and return to the Company the AGMS Proxy Form, appointing a proxy holder designated by the Company and providing voting instructions in connection with the Meeting. The AGMS Proxy Form must be received by the Company ON OR BEFORE 19th APRIL 2021 AT 24:00 (MIDNIGHT), CENTRAL EUROPEAN TIME (i.e. THE SHAREHOLDERS' RECORD TIME). Please note that in the event that the Company does not receive the AGMS Proxy Form, properly completed and signed, by the date indicated above, you will not be able to vote at the Meeting.

Any shareholder wishing to vote at the Meeting is required to provide reasonably satisfactory evidence to the Company (prior to the Meeting) as to the number of shares of the Company held by such shareholder on the Shareholders' Record Time. Such evidence of shareholding must be provided by means of a certificate issued by the relevant shareholder's bank or stockbroker, which must include at least shareholder's name, shareholder's registered office/address, shareholder status, number of shares held by the shareholder on the Shareholders' Record Time, the stock exchange on which the shareholder's shares trade and signature of the relevant shareholder's bank or stockbroker (the "Certificate of Shareholding"). The Certificate of Shareholding must be delivered to the Company as soon as possible and in any event must be received by the Company ON OR BEFORE 26th APRIL 2021 AT 24:00

(MIDNIGHT), CENTRAL EUROPEAN TIME.

In compliance with the Shareholders' Rights Law and other applicable laws and regulations, this convening notice (which contains the agenda for the Meeting and the procedures for voting at the Meeting), the total number of shares of the Company and voting rights as of the date of this notice, the Shareholder Meeting Brochure and Proxy Statement (which contains reports on each item of the agenda for the Meeting and draft resolutions proposed to be adopted at the Meeting), the Company's 2020 annual report (which contains the Company's consolidated financial statements as of and for the year ended 31st December 2020, and the

Company's annual accounts as at 31st December 2020, together with the external auditors' reports and the consolidated management report and certifications), the 2020 Compensation Report, the AGMS Proxy Form and the model Certificate of Shareholding, required to be submitted to the Company for purposes of voting at the Meeting, are available to shareholders as of the date of this notice, and may be obtained free of charge from the Company's website at ir.tenaris.com/corporate-governance/annual-general-meetingor at the Company's registered office in Luxembourg. In addition, shareholders registered in the Company's registry can obtain electronic copies of these documents free of charge by sending an electronic message to the following electronic address: [e-mail].

The AGMS Proxy Form and the Certificate of Shareholding must be received by the Company, properly completed and signed, by the dates indicated above, at any of the following postal addresses, or by electronic message to the following electronic address: [e-mail].

Luxembourg:

26, Boulevard Royal, 4th Floor, L-2449 Luxembourg

Attn: Adélia Soares

Italy:

c/o Dalmine S.p.A.

Piazza Caduti 6 luglio 1944 n. 1 24044 Dalmine (BG)

Attn: Marco Maria Domenico Tajana and/or Francesco Giuseppe Bettiol

Mexico:

c/o Tubos de Acero de México, S.A. Campos Elíseos 400-Piso 17

Col. Chapultepec Polanco 11560 Ciudad de México

Attn: Ulises Martínez Martínez / Carol B. Clemente Bejarano

In the case of shares held through fungible securities accounts in Mexico, the Certificate of Shareholding must be issued by S.D. Indeval Institución para el Depósito de Valores, S.A. de C.V. (Paseo de la Reforma #255, 3er. piso Col. Cuauhtémoc, Mexico City) in accordance with applicable regulation.

The AGMS Proxy Form will only be valid if it includes the shareholder's name, registered office/address and signature and, in the event of shares owned by a corporation or any other legal entity, the name, registered office/address and signature of the individual(s) representing such corporation or other legal entity. INCOMPLETE OR ERRONEOUS AGMS PROXY FORMS OR AGMS PROXY FORMS WHICH ARE NOT TIMELY DELIVERED OR DO NOT SATISFY THE REQUIRED FORMALITIES WILL BE DISCARDED AND THE UNDERLYING SHARES WILL NOT BE VOTED AT THE MEETING.

The proxy holder voting at the Meeting will be a person designated by the Company and appointed in the AGMS Proxy Form by each shareholder electing to vote by proxy at the Meeting. Accordingly, the proxy holder will represent all shareholders electing to vote by proxy at the Meeting and will vote the shares of the represented shareholders differently, in accordance with the instructions given to the proxy holder by each shareholder.

Each share is indivisible for purposes of voting at the Meeting. Co-owners of shares, beneficiaries and bare-owners of shares, and pledgors and pledgees of pledged shares may only submit one AGMS Proxy Form.

In accordance with the Shareholders' Rights Law, shareholders holding, individually or collectively, at least five per cent (5%) of the issued shares of the Company have the right to

1. include items on the agenda for the Meeting; and (b) propose draft resolutions for the items included or to be included on the agenda for the Meeting. To exercise such rights, shareholders holding, individually or collectively, at least five per cent (5%) of the issued shares of the Company, must submit a written request to the Company ON OR BEFORE 12TH APRIL 2021, to any of the postal addresses of the Company indicated above, or by sending an electronic message to the following electronic address: [e-mail]. The request must be accompanied by a justification or a draft resolution proposed to be adopted in the Meeting and must include the postal or electronic address at which the Company can acknowledge receipt of such request. Requests which are not timely delivered or do not satisfy the required formalities will be discarded and the proposals included in such requests shall not be included in the agenda for the Meeting.

Holders of ADRs: procedures for voting at the Meeting

Holders of American Depositary Receipts ("ADRs") as of 19th APRIL 2021 (the "ADR Holders' Record Date") are entitled to instruct DEUTSCHE BANK TRUST COMPANY AMERICAS, as Depositary (the "Depositary"), as to the exercise of the voting rights in respect of the Company's shares underlying such holder's ADRs. Only those ADR holders of record as of the ADR Holders' Record Date will be entitled to provide the Depositary with voting instructions.

Proxy materials will be available to ADR holders as of the date of this notice on the Company's website at ir.tenaris.com/corporate-governance/annual-general-meeting. Voting instructions and voting cards will be sent to ADR holders by the Depositary. Any eligible ADR holder who wishes to give voting instructions in respect of the shares underlying its ADRs must follow the instructions and meet the deadlines set forth in such voting instructions and voting cards.

In accordance with the Luxembourg Law of 11th January 2008 on transparency obligations for issuers of securities, as amended, each shareholder of the Company must notify the Company and the Luxembourg Commission de Surveillance du Secteur Financier (CSSF) on an ongoing basis whenever the proportion of the Company's voting rights held or controlled by such shareholder (or shareholders acting in concert) reaches, exceeds or falls below any of the following thresholds: 5%, 10%, 15%, 20%, 25%, 33 1/3%, 50% and 66 2/3%. Any such notification shall be made as indicated in the Company's website at tenaris.com/en/sustainability/governance-and-ethics/and in accordance with CSSF regulations. Failure to make such notification will cause the suspension of the exercise of voting rights relating to the shares exceeding the proportion that should have been notified.

On 30th March 2021, the Company had a total issued share capital of US$1,180,536,830, represented by 1,180,536,830 shares, each share carrying one vote.

Cecilia Bilesio

Secretary of the Board of Directors

30th March 2021