Sierra Leone has signed a $225 million offshore petroleum licence agreement with Nigeria-based Marginal Energy Limited, in a move aimed at reviving interest in its largely under-explored upstream sector.

The agreement, announced on Thursday, April 23, 2026, grants Marginal Energy exploration and production rights across five offshore blocks—G-145, G-146, G-147, G-160 and G-161—covering approximately 6,800 square kilometres. The deal was executed through the country's Petroleum Directorate.

According to the government, the Nigerian independent has committed to a seismic and drilling programme, with exploration spending expected to exceed $225 million. The investment signals renewed momentum in Sierra Leone's efforts to attract capital into its frontier oil basin, which has seen limited activity in recent years.

Under the terms of the agreement, Sierra Leone will retain a 10% carried interest in oil projects and a 5% stake in gas during the exploration and development phases. The government also holds an option to increase its participation by up to an additional 9% on a paid basis once production begins.

The signing took place at the Invest in African Energy conference in Paris, where Sierra Leone has been promoting its offshore assets to global investors. The government is also preparing a new offshore licensing round, supported by fresh seismic data, as part of broader efforts to stimulate exploration activity.

President Julius Maada Bio said the agreement reflects the country's intention to develop its petroleum resources while ensuring national benefits.

However, Sierra Leone faces the challenge of translating exploration commitments into commercially viable discoveries, as global energy companies weigh investment risks in frontier markets.

The deal marks one of the most significant upstream commitments in Sierra Leone in recent years, highlighting a renewed push to position the country as an emerging player in West Africa's oil and gas landscape.