St. Martin's Island is a small island (area only 3 km2) 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 Chera Dwip. It is about 8 kilometres (5 miles) west of the northwest coast of Myanmar, at the mouth of the Naf River.The only way to reach St. Martin's Island is by water transportation: boats and ships