Saint Martin's Island: Bangladesh's Only Coral Island

Saint Martin's Island is the last piece of Bangladesh. It lies in the north-eastern Bay of Bengal, about nine kilometres south of the tip of the Cox's Bazar–Teknaf peninsula and roughly eight kilometres west of the Myanmar coast at the mouth of the Naf River, and it forms the southernmost part of the country. Local people call it Narikel Jinjira — Coconut Island — and the whole country knows it by a title it carries everywhere: Bangladesh's only coral island. That title is broadly deserved and slightly misleading, and both halves of that sentence matter to understanding what this place is and what is happening to it.

A Small, Flat, Three-Part Island

The island falls under Teknaf Upazila of Cox's Bazar District and constitutes a single union, Saint Martin's. Banglapedia places it between 20°34′ and 20°39′ north latitude and 92°18′ and 92°21′ east longitude. It is 7.315 kilometres long, aligned north-north-west to south-south-east, almost flat, and — by Banglapedia's measurement — just 3.6 metres above mean sea level. Geomorphologists describe an island of about eight square kilometres at low tide that shrinks to around five square kilometres when the tide comes in; the legally protected land area, the Ecologically Critical Area, is 590 hectares.

Its shape is a dumbbell. The northern third is Uttarpara, also called Narikel Jinjira, where the jetties, markets, schools and most homes stand, and where a shallow lagoon in the middle connects to the sea at high tide. A narrow central belt, Maddhyapara, pinches at a collar called Golachipa — the "narrow neck" — where storm surges can wash across from side to side. South of it lies Dakshinpara, broader again, with two small dead lagoons, marshy ground and a long narrow tail running off to the south-east. Beyond the tail, separated from the main island at high tide, sits Chhera Dwip: a scatter of low rocky islets that forms the southernmost land in Bangladesh. Nobody lives there; its one patch of green is a small stand of bush, and its shores hold some of the island's most important coral colonies.

Built of Shell and Sandstone, Fringed with Coral

The phrase "coral island" suggests an atoll — land built by coral itself. Saint Martin's is not that. Banglapedia's own entry on Ecologically Critical Areas classifies it plainly as a "sedimentary continental island", and the geology bears that out. The island is the uplifted crest of an anticline on the Chittagong–Tripura fold belt, the same folded hill system that runs down the Teknaf peninsula. Its bedrock is the Bokabil Formation — Miocene sandstone and shale of the Surma Group — capped by a much younger bed of coquina, a limestone made of cemented mollusc shells, together with coralline limestone. The island's fresh water, such as it is, sits in that porous shelly limestone, which is why wells a short distance apart can differ so sharply in quality.

Coral enters the story as a tenant, not the landlord. Banglapedia records that living corals occur as small colonies in sheltered pools very near low-tide level and in the shallow sea around the island, growing mostly on beach rocks and calcareous sandstone concretions — boulders, in plain terms, rather than on a reef framework of their own making. What surrounds the island is best described as a rocky reef on which coral-algal communities grow; Banglapedia calls it one of the few areas in the world where coral-algal communities dominate rocky reefs. A 2020 study in the Ocean Science Journal puts the correction bluntly: the sedimentary rocky reef around the island is "often misunderstood as 'coral reef'".

None of this makes the coral young or trivial. Banglapedia's coral entry catalogues 21 species of fossil corals from the island, the oldest radiocarbon-dated to 33,238 years ago, in the Late Pleistocene: corals have lived and died around these rocks since before the last glacial maximum. The same entry explains why so much of that coral now stands dead and dry. The island is rising. An emerged coquina cliff on the Dakshinpara coast, three metres high, has been dated from about 450 years old at its base to 292 years at its top, and Banglapedia calculates a mean uplift rate of some 19 millimetres a year from its radiocarbon evidence; dead corals lifted above the level at which they grew are, in its phrase, still in the process of emerging. Saint Martin's is thus an island moving in two directions at once — pushed up by tectonics along its fold, gnawed down by the sea along its shores.

So the honest version of the famous title is this: Saint Martin's is the only place in Bangladesh where reef-building corals form living communities — on the flanks of a sedimentary island that was never built by them. The marketing shorthand survives because the longer sentence does not fit on a brochure. Scientifically, the longer sentence is the interesting one.

Names and Settlement

The island was once part of the Teknaf peninsula, until the sea submerged the low neck of land and cut it off. Its recorded human story begins with mariners rather than settlers. The island is said to have been named "Jazira" — simply "the island" in Arabic — by Arabian merchants who used it as a staging point, and the first settlement is conventionally dated to the eighteenth century and credited to them. Later, Bengali-speaking Rakhine fishing families settled, planted the coconut groves the island is still known for, and gave it the name locals use today: Narikel Jinjira, Coconut Island. A third name, Daruchini Dwip — Cinnamon Island — survives in local usage. The English name is said to date from the British period and to honour O. M. Martin, who was Divisional Commissioner of Chittagong from 1938 to 1940.

For an island now famous as a destination, Saint Martin's remained a working fishing settlement for most of its settled life, and in essentials it still is one. Banglapedia records about 3,700 people in 535 families, most of them fishermen. That figure is now well out of date: recent reporting puts the resident community far higher, and in October 2026 the acting chairman of Saint Martin's Union Parishad spoke of around 10,500 residents whose livelihoods depend on the island's economy. Fishing remains the mainstay, supplemented by small farming — Banglapedia lists onion, watermelon and a little rice — coconut and betel nut, fish drying, and the seasonal trade that visitors bring. The islanders' harder constraints have not changed with the times: sweet water is scarce, drawn from a few ponds and tubewells, and during the monsoon the sea crossing to Teknaf can become dangerous enough to leave the island effectively cut off.

Life on the Reef and Shore

What elevates this small island into a site of national scientific importance is the density of life packed around it. Research by the Department of Environment, carried out with UNDP assistance and reported in 2010, recorded 153 species of seaweeds, 66 species of coral, 240 species of fish, 120 species of birds, 29 species of reptiles and 29 species of mammals on and around the island, across an unusual stack of ecosystems: coral-rich areas, mangrove patches, lagoons and stony shores. Banglapedia's own terrestrial tally is different — 182 wildlife species, including 130 birds — a reminder that every count is a snapshot taken by a particular survey in a particular season.

Even the coral count depends on who is counting. The geological work catalogued by Banglapedia identified 39 living coral species, with Porites, Favites, Goniopora, Cyphastrea and Goniastrea the most abundant, while the DoE survey reported 66. The numbers are not necessarily in conflict: they come from different methods, different decades and different definitions of the survey area. What researchers agree on is the direction of travel, and it is downward.

The island's best-known residents arrive in winter. Olive ridley turtles come ashore on dark nights to nest in the sand, the regular nesting species here; green and hawksbill turtles are recorded in the surrounding waters. Nesting turtles and their eggs face dogs, artificial light and disturbance, so the Department of Environment now gathers eggs into guarded hatcheries. In the 2024–25 season, officials collected 5,022 eggs from 45 nests laid by 61 turtles between early December and late February, and released hatchlings from the two hatcheries at Golachipa and Konarpara; about 1,500 eggs were lost to dogs. The season before, only about 20 turtles had nested. Department officials attributed the near-tripling to the strict limits then in force on visitors — the clearest evidence yet that the island's wildlife responds quickly when pressure is lifted. Offshore, the protected waters hold Indo-Pacific humpback dolphins, whale sharks and rays alongside the fish stocks the islanders depend on.

Declared Worth Protecting

The state recognised the island's fragility early, at least on paper. On 19 April 1999, Saint Martin's was declared an Ecologically Critical Area under the Environment Conservation Act 1995 — 590 hectares covering the island in its entirety. A follow-up gazette that July prohibited activities destructive to its flora and fauna, restricting the extraction of coral, seashell and conch, the felling of trees and the building of structures. In January 2022 the protection went offshore: on 4 January, the government declared 1,743 square kilometres of the surrounding Bay of Bengal, down to a depth of 70 metres, as the St Martin's Marine Protected Area under the Wildlife (Conservation and Security) Act 2012. It was the country's largest marine protected area and its second, created after at-sea surveys and community consultations by the Wildlife Conservation Society, and it placed the island in the same small class of formally protected ecosystems as the Sundarbans — except that Saint Martin's entire protected land area would fit inside a single village-sized corner of the mangrove forest.

Designation and enforcement, however, have never been the same thing here. Construction went ahead for years inside the ECA, much of it without Department of Environment clearance, and the rules that did exist were honoured irregularly. The gap between the island's paper status and its lived reality is the central fact of its recent history.

Pressure and Loss

Measured against its recent past, the island is measurably poorer. A geospatial study published in the Ocean Science Journal in 2020 estimated that Saint Martin's lost about 70 percent of its reef between 1980 and 2018, attributing the loss to human pressures — coral and shell extraction, construction, anchoring, pollution and crowding. The authors were candid that field data are scarce; 70 percent is a remote-sensing estimate, not a census. But no available evidence points the other way.

The land itself is also on the move. A shoreline analysis by researchers at Jagannath University, tracking satellite imagery from 1974 to 2021, found that about 55 percent of the island's shoreline transects were eroding, that the coastline had shortened by some 790 metres, and that the island lost 0.22 square kilometres of land while gaining 0.14 — a small net loss with a sharp geography: Uttarpara, the settled north, is eroding fastest, in places by more than two metres a year, while Dakshinpara in the south is still gaining ground, sheltered, the researchers note, by its coral colonies. The same study recorded the human footprint expanding across those decades, the built-up settlement area growing from about two hectares to nearly 29. The researchers' modelling adds a longer shadow: if emissions remain high, they project, around 70 percent of the island could be under water by 2150. That is a projection, not a prediction — but on an island whose highest ground is a few metres of shell limestone, even gentle versions of the future arrive quickly.

The Island as of November 2026

As of November 2026, access to Saint Martin's is rationed in the name of the protection it was promised in 1999. After an inter-ministerial meeting on 12 October 2026, the environment ministry fixed the 2026–27 tourist season from 1 November 2026 to 15 March 2027, with the daily number of visitors capped at an average of 3,500 — raised from the previous 2,000 — and each visitor paying a Tk 100 environment conservation fee collected under the Ecologically Critical Area Management Rules 2016. Tourist ships sail only from the Nuniyarchhara jetty in Cox's Bazar, visitors travel on an online pass with a QR code, single-use plastic is banned, and Chhera Dwip remains closed to tourists altogether, as it has been since 2020. A revised directive on 27 October allowed overnight stays throughout the season; even so, no ship sailed for the first four days of November while approvals were completed, and the season's first tourist sailing took place on 5 November.

Whether this regime of caps, fees and closed months will be enough is the open question the island now poses. The turtle season of 2024–25 suggested the ecosystem recovers fast when given room. The shoreline studies suggest the island's physical margin for error is thin and thinning. Saint Martin's has been declared critical, declared protected and declared a marine reserve; its next chapter depends on whether the declarations are finally made to hold.