The atolls of the Maldives are formed from coral structures. The atolls are part of a greater structure known as the Laccadives-Chagos Ridge, which stretches over 2,000 kilometers.

An atoll is a group of islands with a reef that nearly or entirely encloses a ring-like lagoon. The Maldives has 26 naturally occurring atolls which are divided into 21 administrative ones.