The Chagos Archipelago, which is claimed by the United Kingdom as the British Indian Ocean Territory (BIOT) lies about 1,770km east of Mahé (the main island of the Seychelles). It consists of about 60 low-lying coral islands, and covers some 640,000 sq km of ocean. The total land area is only about 60 sq km.
Diego Garcia, the largest and most southerly island, is 44 sq km in land area. It houses a joint UK/US Military base.
Access to BIOT
The United Kingdom controls all access to the Territory, for which a permit is mandatory. There are no commercial flights and permits are only issued to yachts in safe passage. Tourism and visits are not encouraged by the UK Government.
Yachts are permitted to moor at specified locations in Salomon and Peros Banhos atolls for a maximum stay of 28 days at a fee of £50 for each 7 days - FCO BIOT Entry Permits [Visiting Vessels Mooring Fees and Permit Regulations 2006 Amendment Regulations 2010].
Access to Diego Garcia
Access to Diego Garcia is further restricted and is only permitted to those with connections to the military facility. No unauthorised vessels or yachts are permitted to approach within 3 nautical miles (the limit of the Territorial Sea).
The US/UK Exchange of Notes 1972 [see page US/UK Agreements] defines those who may enter the island:
In addition, the UK Government is permitted to grant access to "members of scientific parties wishing to carry out research on Diego Garcia and its environs, provided that such research does not unreasonably interfere with the activities of the facility". Prior consultation for this is required with the US.
Aside from these groups, any access requires prior consultation with US authorities.