Discovery in Block SK405B, off the coast of Sarawak, offshore Malaysia

March 30, 2021 Project

Mitsui Oil Exploration Co., Ltd. ("MOECO", Head Office: Tokyo, President & CEO: Hirotaka Hamamoto) is pleased to announce that a discovery of oil and natural gas from the first exploration well, Sirung-1, has been made in Block SK405B, located off the coast of

Sarawak, offshore Malaysia.

MOECO Oil (Sarawak) Sdn. Bhd., a wholly owned subsidiary of MOECO, participates in Block SK405B with 25.5% participating interest together with PTTEP Sarawak Oil Limited, as the Operator with 59.5% participating interest and PETRONAS Carigali Sdn. Bhd.

with the remaining 15% participating interest. These parties will continue exploration activities in Block SK405B to evaluate quality and quantity of the reserves for possible future development.