Best Spots for Scuba Diving in Thailand

Five islands about 60 km off Khao Lak, and the shallowest good diving in the Andaman: hard coral reef starts a few metres off the beach, so it suits snorkellers and newly qualified divers as much as anyone. Ko Surin Tai holds a Moken sea nomad village. The national park is open 15 October to 15 May only.

Known For : Diving and Snorkelling

Granite boulder islands roughly 70 km off the Phang Nga coast, and the Andaman's signature dive destination. Nine islands gave the group its name, from the Malay for nine, and the park now covers eleven. The west sides are boulder swim-throughs, the east gentle coral slopes. Open 15 October to 15 May only.

Best Time: November to April

1 Similan Attractions

A horseshoe of limestone pinnacle standing alone in open water inside the Surin park, and the best whale shark odds in the Andaman. The rock is smothered in purple soft coral, and the small stuff is the real draw: seahorses, frogfish, harlequin shrimp, tigertail seahorses. Reached by liveaboard or long day trip from Khao Lak.

Known For : Nightlife in Phi Phi Island Maya Bay Koh Phi Phi Leh

The easiest serious diving to reach in the Andaman, run out of Phi Phi Don or as a day trip from Phuket. Bida Nok and Bida Nai are the two limestone outcrops off the southern end and hold the best of it, with leopard sharks on the sand and a soft coral archway. Shallow enough in places to snorkel the same reef.

Best Time: November - April

24 Phi Phi Islands Attractions

Two open water pinnacles about 70 km southwest of Koh Lanta in the Andaman Sea, not in Phang Nga Bay as often written. Hin Muang is the deepest wall in Thailand, dropping well past 50 metres under red and purple soft coral. Currents are strong and there is no shallow refuge, so these are advanced dives and the best manta odds in the country.

Known For : Koh Nang Yuan Hike to John Suwan Viewpoint Sairee Beach

Around 25 dive sites within boat reach of one small island, and the cheapest place in the world to qualify, which is why it certifies more divers a year than almost anywhere. Twins and Japanese Gardens are the training sites, shallow and calm. Diveable all year, with the Gulf at its clearest roughly February to September.

Best Time: December to September

25 Koh Tao Attractions

A passenger ferry that struck Anemone Reef in 1997 and sank with everyone aboard rescued, now Phuket's best known wreck. It sits between about 12 and 30 metres, and two and a half decades of collapse mean the interior is no longer safe to penetrate. Barracuda and huge schools of glassfish have taken it over.

A granite pinnacle about 45 minutes northwest of Koh Tao, topping out around 14 metres and falling past 35. It is the site people come back to Koh Tao for: grey reef sharks, big schools of trevally and barracuda, and the occasional whale shark in the plankton months. Depth and current make it an advanced dive.

The biggest wreck in Thailand, a former United States Navy landing ship handed to the Thai navy and deliberately sunk off Koh Chang in 2012 to build an artificial reef. Around 100 metres long and lying between roughly 5 and 30 metres, so the upper decks are within reach of newly qualified divers.

A granite pinnacle in open water between Koh Tao and Koh Phangan, not off either, which is why it is a boat ride from both. Its signature is a vertical chimney you enter at about 6 metres and exit near 18. Whale sharks turn up more often here than anywhere else in the Gulf, most reliably in the plankton months.

Limestone pinnacles about 25 km east of Phuket, named for the leopard sharks that rest on the sand around them. They are harmless bottom dwellers rather than anything to worry about, and they are the reason to come. The rock is covered in purple soft coral and the site sits inside a protected marine area.

Known For : Chaweng Beach Fisherman's Village Ang Thong National Marine Park

Thailand's second largest island, and a base rather than a dive site in itself. The local reefs at Koh Wao and Hin Bai are pleasant and shallow, but the diving Samui is really used for is the boat out to Sail Rock, and Koh Tao is close enough to visit for a day. Good for a trip where only some of the party dive.

Best Time: January to September

57 Koh Samui Attractions

A tiny island joined to the northwest corner of Koh Phangan by a sandbar at low tide, off Mae Haad, and the best beginner reef in the Gulf. The coral starts in waist deep water and there is no current to speak of, so it is where Koh Phangan schools take open water students and where snorkellers get the same reef.

Known For : Waterfalls in Koh Chang

The Gulf coast option, near the Cambodian border and far from the crowds on both dive coasts. Alongside the HTMS Chang wreck there are pinnacle dives at Hin Luk Bat and Hin Rap, with soft coral and schooling fish. The season runs roughly November to April, the opposite of the Gulf islands further south.

Best Time: November to March

9 Koh Chang Attractions

North of the Similans and inside the same national park, a pinnacle with strong current and the big schooling fish that come with it. Landings on the island itself have been restricted since 2016 to let the beach recover, but the dive site is still run from Khao Lak. Open 15 October to 15 May only.

A limestone ridge at the northern end of the Similan park and the most reliable manta ray site in the Andaman. The west ridge is a sheer wall where the mantas come in to be cleaned, usually in the plankton months from February to May. Little coral compared with the Similans proper, and that is not the point here. Open 15 October to 15 May.