Scuba diving in Thailand

The best dive sites in Thailand

The best dive sites in Thailand sit on two coasts: Sail Rock and Chumphon Pinnacle in the Gulf, and the Similan Islands and Richelieu Rock in the Andaman.

• Sail Rock, between Koh Tao and Koh Phangan
• Chumphon Pinnacle, off Koh Tao
• Richelieu Rock, in the Surin Islands
• The Similan Islands
• The reefs around Koh Tao, for beginners
• Phi Phi's reefs, on a day trip from Phuket

Pick your coast by the month: the Gulf from March to September, the Andaman from mid-October to mid-May.

See our Thailand island hopping guide, and ask Tanner which coast fits your dates.

Koh Tao: the place to learn to dive

Scuba diving in Thailand for beginners starts on Koh Tao, with warm water and dive centres all over the island.

A PADI Open Water course takes about three days if you do the e-learning before you arrive, says Black Turtle Dive, with five pool dives and four in the sea.

The Open Water card lets you dive to 18 metres.

See our Koh Tao scuba diving guide.

Do the e-learning at home, and three days on Koh Tao gets you certified. Ask Tanner to book the school.

Sail Rock and Chumphon Pinnacle

Sail Rock and Chumphon Pinnacle are the Gulf's big dive sites, both reached by boat from Koh Tao.

Sail Rock sits midway between Koh Tao and Koh Phangan, from 5 to 40 metres, with a vertical chimney you swim up from 18 to 6 metres.

Chumphon Pinnacle is a granite seamount about 11 km north-west of Koh Tao, from 14 to 35-plus metres.

Both suit certified divers. Whale sharks show up most from March to May, with a second window in September and October, says The Manduls (July 2026). Ask Tanner to time the trip for them.

The Similan Islands and Richelieu Rock

The Similan Islands and Richelieu Rock are the Andaman's best diving.

Richelieu Rock, in the Surin Islands National Park north of the Similans, is about 90 minutes by speedboat from Khao Lak, says Dive Happy. Whale sharks are a rare bonus there, not a promise.

The Similan national park is open from 15 October 2026 to 15 May 2027, the Government Public Relations Department says (checked November 2026), and it closes every year from mid-May to mid-October.

Most divers reach both by liveaboard from Khao Lak or Phuket. See our day trips from Phuket.

October to May is the only window, so ask Tanner to book the liveaboard early.

What it costs

Scuba diving prices in Thailand are low by world standards. Big Blue Diving's 2026 budget guide has the Koh Tao numbers in the table below.

At Black Turtle Dive, Open Water is ฿12,950, with equipment, a dive computer, boat trips and dive insurance included. Check what each school includes before you book.

For a group, book the course and the dive boat together. Ask Tanner for one price for the lot.

Your first dive

First-timers start on Koh Tao, with a try-dive or a full Open Water course.

Black Turtle Dive keeps it to 4 students per instructor, and the first two sea dives stay above 12 metres.

Beginners need no experience; the course teaches the theory, then the pool, then four dives in the sea.

Allow three to four days. Ask Tanner to put the course before the party nights, not after.

When to skip Koh Tao

Skip Koh Tao for diving from October to December, when SSI warns of rain and rough seas.

Diving still runs on the sheltered side of the island, says SSI, but it's not the trip you came for.

From October to December, switch coasts: the Andaman season opens in mid-October.

See our best time to visit Koh Samui.

Diving in November? Go west to the Andaman. Ask Tanner to move the trip to Khao Lak.

Diving in August

August means the Gulf: Koh Tao, Sail Rock and Chumphon Pinnacle, while the Andaman's parks are closed.

March to September is the Gulf's best stretch, with visibility often over 20 metres, says SSI.

In August you're between the two whale shark windows, so come for the pinnacles and the reefs.

Ask Tanner to book Chumphon Pinnacle for your calmest morning.

Diving on a group trip

For a group trip, diving fits best as a Koh Tao day from Koh Samui or Koh Phangan, or a Similan day from Phuket.

Pair it with the Full Moon Party: base on Samui, then take the boat to Haad Rin on Koh Phangan. Or pair it with a yacht day in the Andaman.

See the Full Moon Party at Haad Rin on Koh Phangan, and Koh Samui yachts, and ask Tanner for the boat.

Snorkelling for the rest of the group

Not everyone wants a tank on their back. The reefs around Koh Tao and Phi Phi are shallow enough for a mask and fins.

On your own boat, the divers go down and the others snorkel off the side, then everyone meets for lunch on deck.

Mixed group? Take the boat, not the dive-school day trip. Ask Tanner for a private boat with room for both.

Before you dive

Expect a medical form before you dive. Some answers, like asthma or heart trouble, need a doctor's sign-off before you get in the water.

DAN, the divers' safety network, advises at least 12 hours before flying after a single dive and 18 hours after several dives or days of diving. Leave a full day to be sure.

Check that your travel insurance covers diving to 18 metres, and keep the party for the night after, not the night before.

Next: our Thailand travel insurance guide. Ask Tanner to set the flight home a full day after your last dive.

Scuba diving in Thailand in short

• What it is: scuba diving on two coasts, the Gulf and the Andaman.

• The Gulf is best from March to September; the Andaman from mid-October to mid-May.
• Koh Tao is the place to learn; Open Water takes about three days and certifies you to 18 metres.
• Sail Rock, Chumphon Pinnacle, the Similan Islands and Richelieu Rock are the big dive sites.
• Whale sharks are seen most from March to May around Koh Tao.
• After several days of diving, wait at least 18 hours before you fly.

Checked November 2026.

Pick your coast and month

Pick your month, then your coast: the Gulf from March to September, the Andaman from mid-October to mid-May.

Then book the course or the dive days, and the villa and the boat around them.

Plan it with Tanner, and he sends back the dive days and the party around them.