Saint Helena, Ascension and Tristan da Cunha

The British Indian Ocean Territory, also known as the Chagos Islands, is centrally located in the Indian Ocean, south of the Maldives, about halfway between Madagascar and Indonesia. The main island, Diego Garcia, is a military facility off limits to anyone not on official duty, but some of the uninhabited outer islands can be visited by independent yachters with advance permission. To quote the