Overview
The British Indian Ocean Territory (BIOT) is a British Overseas Territory consisting of the Chagos Archipelago — roughly 55 small islands and atolls scattered across approximately 640,000 square kilometres of the central Indian Ocean. The largest and most significant island is Diego Garcia, which hosts a major joint US–UK military installation and is the only permanently inhabited island in the territory.
The territory has no permanent civilian population. The Chagossian people, who are indigenous to the islands, were displaced between the late 1960s and 1973 to make way for the military base — a deeply contested chapter in the territory's history that continues to be debated in British courts and international forums. As of 2024–2025, negotiations between the UK and Mauritius over the future sovereignty of the Chagos Archipelago have been ongoing; travelers should verify the current political status before planning any itinerary.
The surrounding waters are protected by the Chagos Marine Protected Area (CMPA), one of the largest marine reserves in the world, and the coral reefs and marine life here are considered among the least disturbed on Earth. However, this ecological significance does not translate into tourism access — the area is off-limits to virtually all civilian visitors.
Before You Go
Access restrictions
Civilian access to BIOT is extremely limited and tightly controlled by the BIOT Administration in London. Entry to Diego Garcia is restricted to authorised military and government personnel, contractors, and their dependants. There is no general tourism pathway.
Some scientific researchers and journalists have historically received special permits from the BIOT Administration to visit outer atolls, but such permits are rare, require substantial lead time, and are granted at the Administration's discretion. Private yachts and vessels occasionally pass through the territory's waters but must obtain prior permission and are generally not permitted to land.
Visas and permits
Entry to BIOT requires explicit prior authorisation from the BIOT Administration regardless of nationality. This is not a standard visa process. For up-to-date guidance on entry requirements, check TravelerPulse's Visas section and consult the official BIOT Administration through the UK's Foreign, Commonwealth & Development Office (FCDO).
Sovereignty context
As of 2024–2025, the future sovereignty of the Chagos Archipelago is subject to active negotiations between the United Kingdom and Mauritius. The legal and administrative status of the territory may change. Verify the current situation through official UK government sources before making any plans.
Getting There
There are no commercial flights or ferry services to BIOT. Diego Garcia is served exclusively by military and government charter flights, accessible only to those with appropriate authorisation.
Private sailing vessels wishing to transit through BIOT waters must apply in advance to the BIOT Administration for a permit. Unauthorised entry into BIOT territorial waters is illegal and will be enforced. Vessels in distress may contact the Diego Garcia harbour authority on international maritime frequencies, but no general anchorage or tourism berthing is available.
For researchers or journalists who have been granted a permit, logistics are typically arranged on a case-by-case basis in coordination with the BIOT Administration. There is no public transport infrastructure connecting BIOT to any other country.
Things to See & Do
For the very small number of individuals who gain authorised access to the outer atolls — primarily scientists and permitted researchers — the Chagos Archipelago offers extraordinary natural experiences. The coral reefs are largely untouched, hosting dense populations of reef sharks, rays, sea turtles, and an exceptional diversity of fish species. The absence of human habitation for decades has allowed ecosystems to recover to near-pristine condition.
Bird life is significant, with large colonies of seabirds nesting across multiple atolls including frigatebirds, boobies, and tropicbirds. Coconut crabs, one of the largest terrestrial arthropods, are also present on several islands.
For the vast majority of people, BIOT is not a destination they can visit. Interest in the Chagossian history and the ongoing sovereignty debate can be explored through books, documentaries, and advocacy organisations such as the Chagos Islands (BIOT) All Party Parliamentary Group in the UK and the Chagossian community organisations based in the UK and Mauritius.
Practical Information
Communication
The territory uses the country calling code +246. Communication infrastructure on Diego Garcia is primarily military. There is no public mobile network or civilian internet infrastructure available to visitors.
Health
There are no civilian medical facilities in BIOT. Anyone entering the territory through official channels should ensure comprehensive travel and medical evacuation insurance is in place. Yellow fever vaccination may be required depending on your country of origin and recent travel history — verify with your physician and the relevant health authority before travel.
Currency
The US Dollar is used on Diego Garcia for base transactions. There are no ATMs or banking services accessible to civilian visitors. The outer atolls have no commercial infrastructure of any kind.
Emergency contact
For British nationals in distress in the wider Indian Ocean region, contact the FCDO via their 24-hour helpline (published on the official FCDO website). Verify the current emergency contact numbers through official UK government channels before travel.
Safety
BIOT is not a destination where standard traveler safety advice applies in the conventional sense. The primary risk for most people is attempting to enter the territory without authorisation — this constitutes a serious legal violation and vessels or aircraft may be intercepted and detained.
The outer atolls, if accessed by permitted researchers, present environmental hazards including strong currents, unpredictable weather, and the complete absence of emergency services. Self-sufficiency is essential, and any visit should be meticulously planned with robust emergency protocols.
The ongoing sovereignty negotiations between the UK and Mauritius mean the political and legal framework governing the territory could shift. Monitor official UK and Mauritian government announcements if you have any stake in travel to or near this region.
