After years of negotiations, the United Kingdom and Mauritius concluded an agreement on May 22, 2025, transferring sovereignty over the Chagos Archipelago to Mauritius. At the same time, the agreement ensures the continued existence of the strategically important British-American military base on Diego Garcia for at least the next 99 years.
Under the terms of the agreement, Mauritius will gain sovereignty over the entire Chagos Archipelago, including Diego Garcia. However, the United Kingdom will retain full operational control of Diego Garcia through a 99-year lease with an option to extend for a further 40 years. For the use of the island, the United Kingdom will pay Mauritius £101 million annually, totaling £3,4 billion over the entire lease term.
Diego Garcia – A strategic pillar of defense
The Diego Garcia base has been a cornerstone of British and American defense strategy for over five decades, providing critical support for operations throughout the Middle East, East Africa, and South Asia. Its capabilities include a deep-sea port, an airfield, and advanced communications and surveillance systems that have been instrumental in counterterrorism and intelligence gathering efforts.
The agreement includes provisions to prevent a foreign military presence on the outer islands of the archipelago. A 24-nautical-mile buffer zone will be established around Diego Garcia to protect the base's operations. Furthermore, a strict joint decision-making process will govern all activities on the remaining islands to ensure that they do not interfere with the base's operations.
British Defense Secretary John Healey emphasized the increasing importance of the military base at Diego Garcia in an increasingly dangerous global situation. Without this base, the United Kingdom's ability to deter terrorists, defend its own interests, and protect troops worldwide would be jeopardized. The agreement will ensure the country's national and economic security for generations to come.
Legal objections and support from the USA
The agreement faced legal challenges from displaced Chagossians who had not been consulted during the negotiations. A High Court injunction initially blocked the signing, but was lifted the same day, allowing the agreement to be concluded.
The US government under Secretary of State Marco Rubio expressed its support for the agreement. After a comprehensive interagency review, it was determined that the agreement ensures the long-term, stable, and effective operation of the joint US-UK military facility at Diego Garcia. Rubio described the base as a critical factor for regional and global security.
Diego Garcia in recent military operations
Diego Garcia's continued operational importance was most recently demonstrated during Operation Rough Rider in early 2025. As part of the U.S.-led campaign to contain the Houthi missile threat in the Red Sea and Gulf of Aden, six B-2 Spirit stealth bombers were deployed to the island's airfield in March. Their mission focused on attacking high-value targets, including missile launch pads and command infrastructure, in response to increased attacks on international shipping.
However, the operation was not without difficulties. At least seven MQ-9 Reaper drones were reportedly shot down by Houthi forces, and there were several near misses involving American aircraft over contested airspace. Following a ceasefire agreement in May 2025, the B-2 bombers returned to Whiteman Air Force Base in Missouri. However, a contingent of four B-52 bombers and F-15E Strike Eagles remained at Diego Garcia as a strategic deterrent and rapid reaction force for the Indo-Pacific and Middle East regions.
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