Koh Tao is small, but it has a huge pull: it is Thailand's diving capital and one of the most famous places in the world to learn to dive. Every year, thousands of travellers come to this Gulf 'turtle island' to get their first diving certification (the PADI Open Water) at an unbeatable price, in warm, clear, shallow waters that are perfect for beginners. The result is a young, relaxed, international island where the underwater world is the star of the show and where it is easy to go from never having dived to being hooked for life.
But Koh Tao isn't just bubbles and air tanks. It is also a beautiful island above the water: the long Sairee beach, with its bars for watching the sunset; spectacular viewpoints like John-Suwan, which looks over two twin white-sand bays; hidden snorkelling bays you reach by boat; and, above all, the tiny neighbouring island of Nang Yuan, three islets joined by a sandbar that make up one of the most famous postcards in Thailand. All in a calm, backpacker-friendly atmosphere with plenty of character.
This guide helps you make the most of Koh Tao whether you are coming to dive or not: how to choose a school and how much the course costs, the best diving and snorkelling spots, which viewpoints and beaches you can't miss, how to get to an island with no airport, how to get around safely and when to go. Whether you want to become a diver or just enjoy turquoise water and sunsets, Koh Tao is one of the most addictive islands in the Gulf of Thailand.
Koh Tao ('turtle island', for the shape of the island and the sea turtles that used to nest on its beaches) was for centuries a practically uninhabited island, covered in jungle and used only occasionally by fishermen. In the early 20th century it had a dark chapter: between 1933 and 1947, the Thai government used it as a penal colony, a place of exile for political prisoners, because of its remoteness and isolation. After the prison closed, the first families of fishermen and coconut farmers (many from neighbouring Koh Phangan) settled there permanently. The island remained a remote corner until, from the 1980s and especially the 1990s, backpackers exploring the Gulf discovered its crystal-clear waters and reefs, and diving began to take off. Within a few decades, Koh Tao became one of the most important and cheapest dive training centres in the world, with dozens of schools certifying a huge number of divers every year. Today the island lives almost entirely from diving and tourism, without completely losing its small scale and relaxed pace. The full history of the island and the Gulf is on our history page.
Read the full history ↓The islands of the gulf: Koh Samui with its coconut palms, Koh Tao, once a penal colony and now a diving mecca, and Koh Phangan, home of the Full Moon Party.
Read the history of South / Gulf of Thailand (eastern islands) →If you book from here we earn a commission and you pay no more. Prices and availability come from Civitatis.
No exact prices: a scale from $ (budget) to $$$$$ (luxury), with 2-3 options per category.
Origins, formation and what the sources say.
The name Koh Tao says it all about its past: 'turtle island'. It's thought to have got the name both from its outline, which supposedly looks like a turtle's shell when seen from the sea, and from the sea turtles that for centuries came ashore to lay their eggs on its sandy beaches. This small patch of land in the north of the Gulf of Thailand, the smallest of the three big islands in the area, spent most of its history as a wild and practically uninhabited place.
Unlike Samui or Phangan, which had settled communities of fishermen and coconut growers, Koh Tao was too small, too remote and too short of resources to support a permanent population. Covered in jungle, with little fresh water and battered by the open sea, the island was only visited now and then by fishermen looking for shelter or working its waters, which were rich in marine life. Nobody stayed: it was a stopover, not a home.
Being a deserted, isolated island with hardly any human footprint shaped Koh Tao for centuries, and it explains why its history as an inhabited place is actually very short and very recent. It was exactly that isolation (a remote island, hard to reach and almost impossible to escape from) that led the Thai government, in the 20th century, to put it to a use as unexpected as it was grim, before the first permanent settlers arrived.
The darkest and most unusual chapter in Koh Tao's history is its time as a penal colony. In 1933, during a turbulent period in Thai politics after the end of absolute monarchy (1932), the government began using the remote, uninhabited island as a prison: a place of exile for prisoners, making the most of how isolated it was and how hard it was to escape from.
The best-known episode came around 1943, when about a hundred political prisoners, linked to the failed Boworadet (Borawadesh) rebellion against the government, were moved to Koh Tao from the prison on Koh Tarutao, in the south. The prisoners and their guards settled in Mae Haad bay, where the main pier and the island's tourist heart are today. Conditions were extremely harsh: supplies were scarce, malaria was endemic in the jungle, and the waters were said to be full of sharks, which made any escape attempt almost impossible.
The prison island didn't last much longer. Because the facility was so remote and costly to run, and amid the political changes after the war, the inmates received a royal amnesty and were sent back to the mainland around 1947, leaving Koh Tao deserted once again. That short but intense prison past, barely visible today to visitors who come to dive, is a reminder that today's 'paradise island' was, not so long ago, a place of punishment and isolation.
After the penal colony closed and the prisoners left around 1947, Koh Tao was deserted again, but not for long. Soon afterwards the first families arrived to settle on the island for good, many of them from neighbouring Koh Phangan, drawn by the chance to set up plantations and live off the land and the sea in untouched territory that was there for the taking.
As on the other islands in the Gulf, those first settlers' economy revolved around the coconut. They planted coconut palms across much of the island and lived off the crop, along with fishing in the plentiful waters around it. It was a very small community of just a few families, living a simple, self-sufficient life in a place that still had no roads, no electricity and no regular link to the mainland beyond the fishing boats.
For several decades, that was the face of Koh Tao: a tiny island of coconut palms and fishermen, even more remote and unknown than its neighbours, with no idea of what lay ahead. The island's great wealth, the one that would change its history forever, wasn't in its coconut groves or its land, but hidden beneath the surface of the sea around it: its coral reefs and crystal-clear waters, which a new kind of visitor was about to discover.
Koh Tao's real revolution came underwater. From the 1980s and, above all, the 1990s, the backpackers travelling around the Gulf islands began to discover what the island hid in its sea: warm, clear, shallow water, coral reefs full of life and excellent visibility, ideal conditions for diving and snorkelling. What had been a forgotten coconut island turned out to be one of the best places in the world to get in the water.
The first dive schools soon opened, and word of mouth did the rest. Koh Tao found its calling and specialised in teaching diving like nowhere else: thanks to its perfect conditions for beginners and fierce competition between operators, it became one of the cheapest and most popular places on the planet to get a diving certificate (the PADI Open Water certification). Every year, tens of thousands of people come to the little island with one goal: learning to dive.
That boom completely transformed Koh Tao in just a few decades. The community of a few coconut-farming families gave way to an island devoted to dive tourism, with hundreds of schools, hotels, restaurants and bars and an international population of instructors and industry workers. The village of Mae Haad (where the prison once stood) and Sairee beach came alive. Turtle island, prison island, coconut island had become the world capital of budget diving.
Today's Koh Tao is, above all, an island devoted to the sea and to diving. It lives almost entirely off underwater and beach tourism, with a young, international energy, dozens of diving and freediving schools, and a steady stream of travellers who come to get certified, go diving or simply enjoy its turquoise water, its snorkelling bays and the postcard view of neighbouring Koh Nang Yuan. Together with Samui and Phangan, it completes the trio of must-see islands in the Gulf.
Success also brought challenges. Rapid growth and the pressure of so many visitors pose serious sustainability problems for a small island with limited resources: the health of the coral reefs (threatened by tourism, warming seas and bleaching), water and waste management, and the protection of the marine environment that is, quite literally, the island's lifeblood. Aware of this, the diving community runs conservation projects, seabed clean-ups and coral restoration.
Koh Tao also carries episodes that have tarnished its image, such as the occasional police case with major international coverage that put the spotlight on safety and on the power of local interests. But beyond the headlines, for most of its visitors the island is still a bright, addictive place, where many people have their first experience underwater and get hooked for life. From turtles to prisoners, from coconut palms to divers: few islands have changed as much, or as fast, as this little 'turtle island' in the Gulf of Thailand.
