St. Martin's Island is located at the mouth of the Naf River.
- It is situated in the northeastern part of the Bay of Bengal, about \(9\text{ km}\) south of the tip of the Cox's Bazar-Teknaf peninsula in Bangladesh.
- Location: Mouth of the Naf River, separating Bangladesh and Myanmar.
- Significance: It is the only coral island in Bangladesh.
- Other Names: Known locally as Narical Gingira (Coconut Island) or Daruchini Dip (Cinnamon Island)