UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Private Issuer
Pursuant to Rule 13a-16 or 15d-16 of the

Securities Exchange Act of 1934

For the month of March, 2026

Commission File Number 1-15106

PETRÓLEO BRASILEIRO S.A. – PETROBRAS

(Exact name of registrant as specified in its charter)

Brazilian Petroleum Corporation – PETROBRAS

(Translation of Registrant's name into English)

Avenida Henrique Valadares, 28 – 9th floor
20231-030 – Rio de Janeiro, RJ
Federative Republic of Brazil

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F ___X___ Form 40-F _______

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes _______ No___X____

New oil discovery in the pre-salt of the Campos Basin
—

Rio de Janeiro, March 26, 2026 - Petróleo Brasileiro S.A. – Petrobras has identified the presence of excellent-quality oil in the pre-salt of the Campos Basin, through an exploration well drilled in the Marlim Sul Field. Well 3-BRSA-1397-RJS is located 113 km offshore, in the municipality of Campos dos Goytacazes (RJ), in 1,178 meters of water depth.

The oil-bearing interval was identified based on wireline logs, hydrocarbon shows (gas indications) and fluid sampling. The samples will be sent for laboratory analyses to characterize the reservoirs and fluids encountered, supporting the continued appraisal of the area’s potential. Drilling operations were completed safely, in compliance with HSE requirements and with respect for the environment and people.

Petrobras’ activities in the Campos Basin are aimed at replenishing oil reserves in mature producing basin, ensuring the company’s sustainability and meeting Brazil’s energy demand during the energy diversification period.

The Marlim Sul Field was discovered in November 1987 through well 4-RJS-382. Petrobras is the operator of the field with a 100% working interest.

www.petrobras.com.br/ri

Para mais informações:

PETRÓLEO BRASILEIRO S.A. – PETROBRAS | Relações com Investidores

E-mail: petroinvest@petrobras.com.br/acionistas@petrobras.com.br

Av. Henrique Valadares 28 – 9º andar – 20031-030 – Rio de Janeiro, RJ

Tel.: 55 (21) 3224-1510/9947

Este documento pode conter previsões segundo o significado da Seção 27A da Lei de Valores Mobiliários de 1933, conforme alterada (Lei de Valores Mobiliários) e Seção 21E da lei de Negociação de Valores Mobiliários de 1934 conforme alterada (Lei de Negociação) que refletem apenas expectativas dos administradores da Companhia. Os termos: “antecipa”, “acredita”, “espera”, “prevê”, “pretende”, “planeja”, “projeta”, “objetiva”, “deverá”, bem como outros termos similares, visam a identificar tais previsões, as quais, evidentemente, envolvem riscos ou incertezas, previstos ou não, pela Companhia. Portanto, os resultados futuros das operações da Companhia podem diferir das atuais expectativas, e, o leitor não deve se basear exclusivamente nas informações aqui contidas.

Map indicates the discovery location in the Campos Basin

www.petrobras.com.br/ri

Para mais informações:

PETRÓLEO BRASILEIRO S.A. – PETROBRAS | Relações com Investidores

E-mail: petroinvest@petrobras.com.br/acionistas@petrobras.com.br

Av. Henrique Valadares 28 – 9º andar – 20031-030 – Rio de Janeiro, RJ

Tel.: 55 (21) 3224-1510/9947

SIGNATURES

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: March 26, 2026

PETRÓLEO BRASILEIRO S.A–PETROBRAS

By: /s/ Fernando Sabbi Melgarejo

______________________________

Fernando Sabbi Melgarejo

Chief Financial Officer and Investor Relations Officer

PETROBRAS - PETROLEO BRASILEIRO SA 6-K