Diving in Koh Tao

Koh Tao — literally “Turtle Island” — sits in the Gulf of Thailand and has earned a near-mythical status in the global diving community. Each year, tens of thousands of first-time divers complete their Open Water certification here, drawn by warm, sheltered seas, affordable prices, and an extraordinary concentration of professional dive centres.

Why Dive Koh Tao?

The island’s sheltered eastern bays offer perfect conditions for beginners: gentle currents, 10–20m visibility, and water temperatures hovering around 28–30°C from March through October. But Koh Tao is no one-trick pony. More experienced divers can push out to the pinnacles — Chumphon and Southwest — where the big stuff happens.

Whale sharks cruise through from March to May and again in September and October. Bull sharks are occasionally sighted at Chumphon Pinnacle. Schools of barracuda swirl over every major site, and the hard coral coverage on the main reef systems is genuinely impressive.

Best Dive Sites

The undisputed headline acts are Chumphon Pinnacle (famous for whale shark encounters and enormous schools of fish) and Southwest Pinnacle (dramatic drop-offs, leopard sharks resting on the sandy bottom). Sail Rock, technically between Koh Tao and Koh Phangan, is a towering underwater chimney regarded by many as the single best dive site in the Gulf of Thailand.

For beginners and improvers, White Rock, Twins, and Shark Island offer excellent reef diving with reliably good visibility and manageable currents.

Dive Conditions

• Best season: March–October
• Water temperature: 27–31°C
• Visibility: 10–25m (peaking April–June)
• Currents: Generally mild; stronger at the pinnacles
• Wetsuit: 3mm shorty or full suit

Getting There

The easiest route is via Koh Samui — a short flight from Bangkok to Samui airport, then a 1h 45m high-speed ferry to Koh Tao. Alternatively, fly into Surat Thani and take the combined bus/ferry package. The journey from Bangkok’s Hua Lamphong station by overnight train to Chumphon, then night ferry, is a rite of passage for backpackers.