With two coasts teeming with life, Thailand is a veritable playground for scuba enthusiasts. Dive shops on Koh Tao, an island in the Gulf of Thailand, certify more new divers than anywhere else in the world.
Koh Tao may be an epicenter for scuba culture, but most of the best spots for scuba diving in Thailand are located on the other side. The Andaman Sea is rich with accessible sites hosting reef dwellers, pelagic, macro, and whatever other marine life you hope to encounter. Diving in Thailand is relatively inexpensive, so you’re probably going to need more pages in your logbook.
As is always the case with diving, conditions can make or break an experience—even at these top places to dive in Thailand. Current and visibility fluctuate, as do the crowds. No one enjoys playing bumper boats at popular dive sites, but you may have to jockey for position during the high season.
The Similan Islands
Any discussion about the best diving in Thailand has to first begin with the famous Similan Islands. Situated far off the west coast in the Andaman Sea, Mu Koh Similan National Park is so beautiful that daily visitor numbers had to be capped to control impact.
The best way to dive in the Similan Islands is by booking a liveaboard package. Visibility is often excellent, but strong currents are common. Warm water temperatures make wetsuits optional. Plenty of whale sharks and mantas pass through between February and April.
Getting There: The most popular jump-off point for the Similan Islands is Khao Lak in Phang Nga Province on the west coast. Excursions also depart from Phuket.
The Surin Islands
Way north of the Similan Islands and equally as beautiful, the five islands of Mu Koh Surin National Park are another top place to dive in Thailand. Like the Similans, the Surin Islands are best enjoyed by booking a liveaboard.
The Surin Islands attract less attention than the Similans—and that’s a good thing. Plankton can affect visibility, but it also draws feeding mantas and whale sharks!
Turtles are common as are blacktip and whitetip reef sharks. The world-famous Richelieu Rock dive site is your best chance for seeing the biggest pelagic creatures materialize from the blue.
Ideal depths for diving range between 10-30 meters and the current is typically less troublesome than in the Similans.
Getting There: The Surin Islands can be reached from Phuket or Khao Lak on the mainland.
The HTMS Kled Kaew
Transliterated spellings differ, but this Royal Thai Navy transport ship was deliberately sunk in 2014 as an artificial reef. Lots of marine life showed appreciation by moving in. Much like the not-so-far-away King Cruiser wreck, lionfish practically run the place.
At over 150 feet long and with a massive cargo hold, the HTMS Kled Kaew wreck is relatively easy to penetrate by experienced divers. You’ll need at least Advanced certification. The ship settled with a slight list between 14 and 27 meters. Strong currents are common.
Getting There: The HTMS Kled Kaew wreck is between Koh Lanta and Koh Phi Phi. You can dive there from either island.
Koh Bida Nok (Koh Phi Phi)
Located just south of the Phi Phi Islands, Koh Bida Nok provides some of the best non-liveaboard diving in Thailand. Access couldn’t be easier, and even wall and cave diving are available on the northern side of the island. An abundance of blacktips, leopard sharks, and banded sea snakes patrol the area.
You’ll find some good swim-through opportunities at nearby Koh Bida Nai, but group snorkeling excursions may be splashing around on the surface. Some exciting macro life such as nudibranchs and seahorses can be found there.
Getting There: Koh Bida Nok and Koh Bida Nai are close to Koh Phi Phi. Some dive trips to the HTMS Kled Kaew may include a second dive in the afternoon at Koh Bida Nok because of the shallow options.
Koh Haa (Koh Lanta)
Koh Haa (five islands) is arguably one of the most exciting places for diving in Thailand. The site is crammed with fun options for divers of all skill levels—although Advanced certification is preferred.
The optional swim-throughs at Koh Haa add an exciting twist, and brave divers can enter a cavern at 20 meters known as The Cathedral. You can surface inside and remove your regulator to test some of the trapped air!
Excellent visibility and a wide variety of life (including plenty of sharks) make Koh Haa a top pick. Due to Koh Haa’s popularity, enjoying a good experience there requires going with a seasoned professional who knows the nooks and crannies of the site.
Getting There: Koh Haa is less than an hour from Koh Lanta.
Sail Rock (Koh Pha Ngan)
Sail Rock, a top dive site located north of Koh Pha Ngan and south of Koh Tao, is widely considered the best in the Samui Archipelago. Barracuda of all varieties, Giant Grouper, and whale sharks frequent the area. Big pelagic stuff isn’t the only draw—nudibranchs and ghost pipefish like to come out to play, too.
Unfortunately, Sail Rock’s notoriety keeps it perpetually busy with dive boats. Try to dive there in one of Thailand's "shoulder" seasons.
Getting There: Sail Rock is best accessed from Koh Pha Ngan, but Koh Tao and Koh Samui also run boats.
Chumpon Pinnacle (Koh Tao)
Koh Tao is a very popular (and cheap) place to become scuba certified in the world. Of the many dive sites within striking distance of the island, Chumpon Pinnacle is considered the best. Depths range between 12 and 35 meters deep; visibility is usually excellent. Whale sharks frequent the site between March and May.
The Southwest Pinnacle, another top dive site in the area, isn’t connected—it’s way south of Koh Tao.
Getting There: Depending on conditions, Chumpon Pinnacle is around 45 minutes from Koh Tao.
Stonehenge (Koh Lipe)
Unlike the prehistoric monument in England, the many granite slabs at the Stonehenge dive site near Koh Lipe aren’t a man-made feature. Instead, they add a natural enhancement to an already great place to dive.
Impressive soft coral begins at around 5 meters deep. The relatively shallow depth allows for colorful photos with abundant light. Large schools of snappers frequent the area as do turtles.
Getting There: Koh Lipe is in the Andaman Sea near the Malaysian border. In fact, you can cross between Malaysia and Thailand there via a small immigration point.
Hin Daeng / Hin Muang
Also in the Andaman Sea, Hin Daeng (Red Rock) and Hin Muang (Purple Rock) are as the names imply: large rocks covered with colorful life. The two rocks, approximately 500 meters apart, take a lot of time and fuel to reach. The payoff can be memorable for experienced divers willing to go the distance.
Hin Muang boasts a wall that plunges to around 65 meters deep! Drifts are spectacular, and schools of giant mantas frequent both rocks. The site hosts plenty of life, big and small. Tuna, barracuda, and jackfish are common, as are their pelagic friends.
With relatively deep dives and rough conditions both above and below the surface, Hin Daeng and Hin Muang aren’t suitable for beginners.
Getting There: Both sites require a long boat trip (sometimes in rough seas) from either Koh Lanta, Koh Phi Phi (2.5 hours), or Phuket. Sometimes divers must surface and wait for conditions to improve. Booking a liveaboard is the best way to score an enjoyable experience at the site.