Cox's Bazar and Chittagong Coast

The southeastern coast of Bangladesh runs from the Chittagong Hill Tracts to the tip of the Cox's Bazar peninsula at Teknaf, where the Naaf River separates Bangladesh from Myanmar. This 120-kilometre stretch of coast, from Cox's Bazar to Teknaf, is an unbroken natural sand beach — the longest in the world. The beach has no significant interruption: no rivers cross it (the drainage runs parallel behind the beach ridge), no headlands divide it, and no significant reef system offshore softens the Bay of Bengal swell. The tidal regime here is semidiurnal, with a large spring range of approximately 3.5 to 4.5 metres. The Bay of Bengal is a semi-enclosed sea with its own resonant tidal characteristics — the basin amplifies the tidal wave as it propagates north, so the range at Cox's Bazar is considerably larger than at the mouth of the Bay in Sri Lanka. At low water springs, the beach at Cox's Bazar drains to a width of 200 to 400 metres of exposed sand, and the full extent of the beach is walkable. At high water springs, the beach narrows to a strip 20 to 50 metres wide between the waterline and the dune or embankment behind. Saint Martin's Island (Narikel Jinjira — Coconut Island in Bengali) lies 9 kilometres south of Teknaf at the southern tip of the Cox's Bazar coast. It is the only coral island in Bangladesh and has the northernmost coral reef in the Bay of Bengal. The reef exists at the thermal limit for coral growth — water temperatures here are marginal for coral in winter months (December to February), and the reef's health reflects the environmental stresses of Bangladesh's heavily fished coastal waters. The island is accessible by ferry from Teknaf, which operates only in the dry season (November to March) when Bay of Bengal sea states are manageable. Inani Beach, 25 kilometres south of Cox's Bazar town, is less developed than the main beach and gives a clearer sense of the coastal character: rock formations at the southern end, a wide sand flat at low water, and fishing boats anchored offshore. The main Cox's Bazar beach has developed as Bangladesh's primary domestic tourism destination, handling millions of visitors annually from Dhaka and Chittagong during the dry season weekends.