Trump signals readiness to defend Diego Garcia base amid UK–Mauritius deal

The future of the U.S.–U.K. military base on Diego Garcia has re-emerged as a point of diplomatic focus after President Donald Trump said the United States would be prepared to act to protect its access if any future arrangement threatened operations there. His remarks followed what he described as “very productive discussions” with British Prime Minister Keir Starmer concerning the long-term status of the base in the Chagos Islands.

Diego Garcia sits at the center of a decades-long dispute over sovereignty, strategy, and international law. While the base remains jointly operated by the United States and the United Kingdom, Britain has agreed to transfer sovereignty of the Chagos Islands to Mauritius under a long-term lease arrangement intended to preserve military use of the facility. The agreement has drawn scrutiny in Washington and London alike because of the base’s pivotal role in U.S. and allied operations across the Middle East, Africa, and the Indo-Pacific.

Trump’s comments signal a calibrated shift in tone from earlier criticism of the agreement, while underscoring Washington’s insistence that uninterrupted access to Diego Garcia remains a national security priority.

Strategic role of Diego Garcia in U.S. operations

In a post on Truth Social, Trump described Diego Garcia as “of great importance to the national security of the United States,” citing its position in the middle of the Indian Ocean. The base hosts long-range bombers, intelligence facilities, logistics hubs, and communications infrastructure that support U.S. and allied missions over vast geographic areas.

Diego Garcia has played a central role in U.S. military operations for decades, including missions connected to Afghanistan and Yemen. Roughly 2,500 U.S. military personnel, contractors, and support staff are stationed there, making it one of the most significant American outposts outside the continental United States.

Trump acknowledged that Britain had negotiated what he called “the best deal he could make” in agreeing to return sovereignty of the islands to Mauritius while retaining a lease for at least 99 years to ensure continued operation of the base.

However, he warned that if “the lease deal, sometime in the future, ever falls apart, or anyone threatens or endangers U.S. operations and forces at our base,” the United States would retain the right to “militarily secure and reinforce the American presence in Diego Garcia.”

A shift in tone after earlier criticism

Earlier in the year, Trump had sharply criticized the U.K.–Mauritius arrangement, calling it an “act of great stupidity” and accusing Britain of weakening its strategic posture. His latest comments indicate a more measured approach, pairing reassurance of cooperation with London alongside a firm statement of U.S. resolve.

According to Downing Street, Trump and Starmer discussed Diego Garcia during a recent call. A No. 10 spokeswoman said the leaders “recognized its strategic importance” and agreed their governments would continue working closely to ensure the base’s future operation.

The British government has emphasized that the deal is structured to protect U.S. and U.K. security interests while addressing longstanding legal and diplomatic challenges surrounding sovereignty of the islands.

The financial and political dimensions of the agreement

Public estimates indicate the arrangement will cost British taxpayers around £35 billion (approximately $47 billion) over the next century. This includes annual payments of roughly £160 million ($216 million) to Mauritius, as well as about £3 billion ($4 billion) in compensation over the life of the deal. The lease includes an option to extend for an additional 50 years.

The agreement has prompted criticism from Britain’s Conservative Party, which argues the deal could weaken the country’s strategic leverage and strain its security relationship with the United States. Critics have raised concerns that returning sovereignty may introduce legal or political uncertainties in the long term.

Mauritius, for its part, has said its sovereignty over the Chagos Islands is “unequivocally recognized” under international law and has urged swift implementation of the agreement. The issue has been shaped by decades of legal challenges and international rulings concerning the status of the islands and the displacement of their original inhabitants.

Ongoing U.S.–U.K. coordination

Downing Street said earlier this year that Britain was working to “allay any concerns” in Washington regarding the arrangement. Officials have emphasized that the lease structure is designed precisely to prevent any disruption to military operations at Diego Garcia.

“We will continue to engage with the U.S. on this important matter and the importance of the deal to secure U.S. and U.K. interests,” a spokesperson said.

The base’s geographic position allows rapid reach into three major regions of strategic focus for Washington: the Middle East, East Africa, and the Indo-Pacific. As global security dynamics evolve, access to Diego Garcia remains one of the few constants in long-range U.S. military planning.

Trump’s remarks, while assertive, underline a broader message of continuity: that regardless of sovereignty arrangements, the United States expects the operational status of Diego Garcia to remain intact.

A base at the crossroads of law, diplomacy, and strategy

The Chagos Islands question combines issues of decolonization, international legal rulings, and contemporary military strategy. For London, the agreement with Mauritius seeks to resolve a lingering historical dispute while preserving critical defense infrastructure. For Washington, the overriding concern is the uninterrupted ability to operate from Diego Garcia without legal or political barriers.

By linking his comments to discussions with Starmer, Trump signaled that coordination with Britain remains central to managing the issue, even as he made clear that U.S. access is non-negotiable.

As the agreement moves toward implementation, Diego Garcia continues to illustrate how historic territorial disputes intersect with present-day security priorities, with both governments seeking to balance legal obligations and strategic imperatives.