Astove Island is part of the Aldabra Group of the Seychelles. It is 38 km SSE of Cosmoledo Atoll, located at 10°06′S 47°45′E. It is a raised coral island of most peculiar form: a single stretch of land, more than 1 km (nearly one mile) at the widest, almost entirely encloses a shallow lagoon. This has a maximum depth of 3 metres (10 ft), and the only exit is a winding passage in the southwest, called Gueule Bras Channel.