St. Martin's Island is a small island in the northeastern part of the Bay of Bengal, about 9 km south of the tip of the Cox's Bazar-Teknaf peninsula, and forming the southernmost part of Bangladesh. There is a small adjoining island that is separated at high tide, called Chhera island. It is about 8 km west of the northwest coast of Myanmar, at the mouth of the Naf River. The first settlement started just 250 years ago by some Arabian sailors who named the island ‘Zajira’. During British occupation the island was named St. Martin Island.It is the only coral island in Bangladesh.