Jammu Dwip is a inhabited delta island in the bay of Bengal. Going there itself is an experience. You need to go to the Benfish Harbor. From there take a motor boat and go there. The boat travels through the river and meets the sea. You will get an experience of flowing into the sea. Keeping Sundarban to your right, you travel an hour into the Bay of Bengal and reach the Jammu Dwip. It's a small island where you can see army of red crabs moving around. Being too close to Bangladesh border, you are not allowed to get down on the island.