Mapped: 6 Best Places to Dive in Thailand

Diving in Thailand

Thailand Similan and Surin islands in the Andaman Sea host some of the best dive sites of South East Asia, accessible only with a liveaboard. If you prefer to relax on an island and do some day trips, there are three other dive sites worth going to.

  • Dive on world-famous Richelieu Rock in Surin islands between February and April to see some whale sharks passing by!
  • On Koh Bon and Koh Tachai sites, manta rays come to clean and feed
  • If you prefer island-based diving, Hin Daeng and Hin Muang near Koh Lanta, and Sail Rock, between Koh Tao and Koh Phangan, are the sites to go to.

The 7 Best Places to Dive in Thailand

Similan and Surin Islands (Andaman Sea)

Established in the early 1980s as national parks, the Similan and Surin islands host Thailand’s top dive sites. They are known for their abundance of marine life and their clear and warm waters surrounding beautiful lush uninhabited islands with white beaches.

Similan islands dive sites are varied with swim-throughs, big boulders, and slopes. Get ready to see some manta rays, some reef and leopard sharks, and plenty of tropical fish.

Richelieu Rock, in the Surin archipelago, has become world-famous for its whale sharks - the best time to see them is between February to April.

Surin islands are close to the Myanmar border and are only accessible with a liveaboard, leaving from Khao Lak or Ranong. Most liveaboards go to Similan and Surin islands in one trip.

liveaboard to similan and surin islands in thailand

The Best Dive Sites of the Similan and Surin Islands

  • Richelieu Rock: Thailand’s most famous dive site is best suited for experienced divers, as its depth goes down to 30 meters (100 ft) and its conditions can vary greatly, being an open-ocean site. Divers usually go around the rock and inside it when it becomes too strong. There are plenty of critters to spot and between February to April, whale sharks might be just around the corner, feeding on plankton. The site is usually very busy, and the best times to jump in are early in the morning or at sunset.

  • Koh Bon: as in Richelieu Rock, currents can vary greatly at this site. Beautiful soft corals can be seen on the wall, where you can also spot some macro and critters. Keep an eye open for manta rays, as they come to Koh Bon to feed and clean.

  • Koh Tachai: as for Koh Bon, be prepared to descend quickly between 14 to 30 meters (45 to 100 ft) as currents can be very strong at the pinnacle. You can often spot some pelagic fish, barracuda, and trevally, and if lucky, some manta rays and whale sharks. Corals in Koh Tachai are beautiful too.

  • Elephant Head Rock: another beautiful pinnacle of the Similan islands, located in the open ocean, so be prepared to find there medium to strong currents. Swim-throughs, boulders, caverns, and channels make it fun to dive on.

whale shark in richelieu rock

Diving Season

  • While you can dive from mid-October to mid-May in Surin and Similan islands, the peak season is between November to April.
  • Whale sharks can be spotted between February to April.

Dive Conditions

  • The Water temperature in Surin and Similan islands ranges 27° to 29°C (81° to 84°F) .
  • Visibility is usually good, and currents are often medium to strong, making it a good destination for advanced divers.

How to Get There

  • Most liveaboards go to Similan and Surin Islands on the same trip, leaving from Khao Lak or Ranong.
  • Check out our liveaboard to Thailand! (3 nights starting from ...), on a recent boat designed by divers, and with a fantastic team!

Phuket, Koh Phi Phi, and Koh Lanta (Andaman Sea)

Two good dive sites are accessible on a day trip from Phuket, or a short boat ride from Koh Phi Phi or Koh Lanta: Hin Daeng and Hin Muang. Located in Mu Koh Lanta National Park, these dive sites are considered the best ones in Thailand after the ones in Similan and Surin islands.

koh phi phi island

The Best Dive Sites of Phuket, Koh Phi Phi, and Koh Lanta

  • Hin Daeng and Hin Muang: you’ll get to dive Thailand biggest vertical wall. With also some caves and caverns, and beautiful red and purple corals, there’s plenty to look at and spot! Grey reef sharks and leopard sharks can frequently be seen, and if you’re lucky, you’ll get to see too some manta rays coming by to get cleaned. Sometimes a whale shark passes by.
manta ray in andaman sea

Diving Season

  • Hin Daeng and Hin Muang diving season is from November to April.

Dive Conditions

  • The water temperature ranges 27° to 30°C (81° to 86°F) .
  • Visibility is usually good, and currents are often medium, making it a good destination for beginners to advanced divers.

How to Get There

  • Hin Daeng and Hin Muang are best reached going with a dive shop from Koh Phi Phi or Koh Lanta. The boat ride lasts one and a half to two hours.
  • From Phuket, it’s a full-day trip.

Koh Samui, Koh Tao and Koh Phangan (Gulf of Thailand)

With cheap dive shops and plenty of places to party, Koh Tao is certainly one of Thailand’s hot spots for a young crowd, eager to learn to dive.

Sail Rock, located between Koh Tao and Koh Phangan, is the best dive site in the area, with whale sharks frequently spotted.

scuba diving day trip from Koh Tao

The Best Dive Sites of Koh Samui, Koh Tao, and Koh Phangan

  • Sail Rock (Hin Bai): located one and a half hours from Koh Tao, Sail Rock has earned its reputation thanks to whale sharks that can be frequently spotted there. The rock rises 8 meters (26 ft) out of the water, and the dive site’s maximum depth is 40 meters (130 ft). You can enter the rock through the “chimney”, located inside the rock at 5 meters (16 ft) depth, and go down to 18 meters (60 ft) where you exit. Marine life is diverse with schools of barracuda, trevally, longfin batfish, and giant groupers to name a few.
whale shark good visibility

Diving Season

  • You can dive on Sail Rock year-round, however, the best time of the year to spot whale sharks is from March to May and October to early December.

Dive Conditions

  • The water temperature ranges 27° to 30°C (81° to 86°F) .
  • Visibility is the best between March to September, reaching up to 30 meters (100 ft).

How to Get There

  • You can reach Sail Rock with a dive shop from Koh Phangan (one-hour boat ride), Koh Tao, or Koh Samui (one and a half-hour ride).

Dive Safety Recommendations

Currents can be strong in Similan and Surin islands, make sure you’re comfortable in currents. Bringing along a Nautilus Lifeline can be a good idea.

For safety reasons, always bring your own surface marker buoy, and use it, even if you’re diving from an island. Unfortunately, several accidents between divers ascending and boats cruising by have been happening in the recent years.

We always recommend having your dive gear, well maintained, you’ll be safer and more comfortable. Light and compact dive gear is particularly suited for travels.

Finally, remember to always use a reef-safe sunscreen.

Thailand Entry Requirements

  • Your passport needs to be valid for at least 6 months from the date of arrival.
  • As of August 2017, no visa was needed for a stay of fewer than 30 days for citizens from France, the USA, Japan, Canada, the UK, Germany, Switzerland, Sweden, Spain, and many other countries.
  • Please check latest visa requirements for Thailand before traveling: Thailand Immigration Bureau
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