Best Dive Sites in Thailand: North, South and East Coast

Thailand still counts some of the best dive sites in the world. From the granite pinnacles and colourful reefs of the Similan Islands to the remote dive sites of the Surin and Tarutao National Parks, the country’s Andaman Sea offers an incredible variety of underwater landscapes and marine life.

Whether you are looking for encounters with whale sharks and manta rays, dramatic pinnacles, coral gardens or easy sites for improving your diving skills, diving in Thailand offers something for divers of many different levels.

Best Dive Sites in North Andaman: Surin Islands

The Mu Koh Surin National Park, near Khura Buri, is a remarkable example of natural beauty, with rare flora and fauna both on land and beneath the surface. Protected by its status as a Thai national park and by environmental conservation programmes, the Surin Islands consist of two main islands: Koh Surin Nuea and Koh Surin Tai.

The waters surrounding the Surin Islands are home to an exceptional variety of marine life. Colourful tropical fish are common, while butterflyfish, moray eels, sharks and sea turtles can also be encountered by divers and snorkellers. One of the most famous visitors is, of course, the whale shark.

Our Favourite Dive Sites in the Surin Islands

• Richelieu Rock – Located east of the Surin Islands, Richelieu Rock is one of our favourite dive sites in the area. The submerged pinnacle is famous for its extraordinary marine biodiversity, with encounters ranging from schooling fish and colourful corals to whale sharks and seahorses. Discover Richelieu Rock.
• Koh Khai (Koh Torinla) – Located south of the Surin Islands, Koh Khai offers a pleasant drift dive around a beautiful pinnacle.
• Koh Chi – North of the Surin Islands, Koh Chi is a good spot for a check dive, with relatively easy conditions and shallow areas.
• Hin Rap – North of Surin Nuea, Hin Rap is one of the deeper dive sites in the Surin area. Large boulders on the eastern side descend to around 25 metres.

Similan Islands: Granite Pinnacles and Colourful Reefs

The Similan Islands are one of Thailand’s best-known diving destinations. The archipelago is part of the Mu Koh Similan National Park, which covers more than 140 square kilometres. Located around 70 kilometres offshore from Phang-Nga Province, the islands are famous for their smooth granite formations, turquoise water, white-sand beaches and coral reefs.

Above and below the surface, the Similan Islands offer spectacular scenery. Underwater, enormous granite boulders create channels, swim-throughs and pinnacles that shelter an impressive variety of marine life.

Our Favourite Dive Sites in the Similan Islands

• Koh Bon – Koh Bon is well known as a cleaning site for manta rays and is one of the places in Thailand where encounters with these magnificent animals are possible. The pinnacle can also offer opportunities to see zebra sharks and abundant reef life. Discover Koh Bon.
• Koh Tachai – Also known as Koh Talu, Koh Tachai became part of the wider protected area and is considered one of the outstanding dive sites in the Similan region. Discover Koh Tachai.
• West of Eden – Situated northwest of Koh Hua Kalok, Island No. 7, and close to Deep Six, West of Eden features a rich underwater landscape where divers can look for mantis shrimp, moray eels, yellow-spotted pipefish and Durban dancing shrimp.
• Elephant Head Rock – Situated between Koh Hua Kalok and Koh Similan, Elephant Head Rock is named for its distinctive shape above the water. Underwater, granite boulders form a maze of channels and swim-throughs at depths of approximately 12 to 30 metres.

Best Dive Sites in the Southern Andaman Sea

The Southern Andaman Sea is home to some of Thailand’s most dramatic offshore dive sites. Two particularly important areas are the Koh Lanta National Park and the Tarutao National Park.

Koh Lanta National Park

Hin Daeng, Hin Muang and Koh Haa are among the best-known dive sites in the Koh Lanta area. Mu Ko Lanta National Park is located in the southern part of Krabi Province and protects a group of islands and surrounding marine environments.

Our Favourite Dive Sites Around Koh Lanta

• Koh Haa – This group of five islands lies between Hin Daeng and Phi Phi and forms part of the Ko Lanta National Marine Park. Depending on conditions and the itinerary, divers may explore Koh Haa Lagoon, Koh Haa Neua and Koh Haa Yai. Swim-throughs, colourful reefs and abundant Andaman Sea marine life make the area interesting for divers of different experience levels. Lucky divers may even encounter leopard sharks or an oceanic manta ray.
• Hin Daeng and Hin Muang – These two spectacular pinnacles rise from the open ocean and are surrounded by deep water. Visibility can be excellent, while the dramatic underwater topography creates a perfect setting for encounters with pelagic species. Manta rays and whale sharks are among the most exciting possible encounters, but there is plenty of smaller marine life to discover as well.

Tarutao National Park and Koh Lipe

Tarutao National Park consists of 51 islands in the Strait of Malacca, off the coast of Satun Province in southern Thailand. This protected area remains relatively remote, and fewer liveaboards venture this far south.

Our Favourite Dive Sites Around Tarutao

• Koh Lipe – Koh Lipe is the only inhabited island in the Butang group within the Tarutao National Park. The island is home to the Chao Ley, often known as Sea Gypsies, as well as resorts, birds, white-sand beaches and numerous nearby dive sites.
• 8 Miles Rock – One of the best-known dive sites in the area, this submerged pinnacle reaches approximately 15 metres below the surface and is surrounded by much deeper water. Its walls are covered with colourful soft corals, including striking purple and pink shades.
• Hin Chabang – This interesting pinnacle features coral gardens and plenty of marine life commonly found in the Andaman Sea. With the top of the pinnacle only a few metres below the surface, the site can be accessible to Open Water divers depending on conditions.
• Super Highway Drift – Between Koh Rawi and Koh Adang, this corridor is known for its strong current and has earned the nickname “Super Highway Drift”. Schools of stingrays can sometimes be encountered along the route.
• Stonehenge – A fantastic dive site with a varied underwater landscape, Stonehenge is known for encounters with leopard sharks and eagle rays.
• Koh Sawang – On the western edge of Tarutao National Park, Koh Sawang is a rocky dive site featuring anemone patches, feather stars and clams. The site is surrounded by deep water and can offer encounters with devil rays, with particularly good visibility possible from November to April.

Best Dive Sites on Thailand’s East Coast: Koh Tao

On Thailand’s east coast, Koh Tao is particularly well known for its accessible diving and dive training. With numerous dive schools and a wide range of dive sites, the island has become one of Thailand’s most popular places to learn to scuba dive.

Koh Tao is surrounded by tropical coral reefs and offers opportunities to encounter a variety of marine life. Whale sharks and rays are among the larger species that can be seen in the area, while hawksbill and green turtles are also associated with the island’s surrounding waters.

Although Koh Tao is famous for beginner-friendly diving, experienced divers can also find interesting marine life and unusual encounters with the right guides and conditions.

Which Part of Thailand Should You Dive?

Thailand’s dive sites offer very different experiences depending on where you travel. The North Andaman is famous for the Similan and Surin Islands, Richelieu Rock and encounters with larger marine life. The Southern Andaman combines dramatic offshore pinnacles such as Hin Daeng and Hin Muang with the islands and reefs around Koh Haa, Koh Lipe and Tarutao. On the East Coast, Koh Tao is particularly well known for accessible diving and dive training.

For divers who want to explore several remote dive sites over multiple days, a Thailand liveaboard is an ideal way to make the most of the Andaman Sea. Instead of returning to shore after every dive, you can wake up close to the next dive site and spend several days exploring reefs, pinnacles and marine life.

At The Smiling Seahorse, our Thailand dive cruises explore some of the most interesting sites in the Andaman Sea, with itineraries designed around the season, weather and diving conditions.

Explore our dive cruises in Thailand