Diving and Snorkelling on Koh Tao: Complete Guide

Why dive on Koh Tao

Koh Tao’s reputation as a dive destination rests on three things: price, accessibility, and variety. An Open Water certification here costs ฿9,000–12,000 — among the lowest in the world for a PADI or SSI course. The dive sites are close to shore (15–30 minutes by boat). And the range of sites — from 3-metre beginner reefs to 40-metre advanced pinnacles — means there’s progression available without changing islands.

Roughly 100,000 divers certify here annually. The volume of dive tourism means competition among schools keeps prices low and standards are high — schools that become known for cutting corners don’t survive.

Dive sites

For beginners and Open Water divers

Japanese Gardens — Between the north tip of Koh Tao and the adjacent Koh Nang Yuan island. Depth: 3–14 metres. High fish density — damselfish, butterflyfish, parrotfish, and sea turtles are commonly seen. Low current and good visibility make it ideal for first open-water dives. Also excellent for snorkelling.

Twins (North and South) — Two coral pinnacles rising from a sandy bottom at 12–18 metres. Sheltered, consistent, good for reef fish observation.

Mango Bay — Sheltered north coast bay with a gentle slope. Marine life includes small reef fish and occasional nudibranch. Good for beginners on the second or third dive.

White Rock — One of the most visited sites. Coral-encrusted boulders from 6 to 18 metres. Hawksbill turtles are reliably seen. Good for snorkelling from shore at the bay edge.

For advanced divers (Advanced Open Water and above)

Chumphon Pinnacle — The best dive site on Koh Tao and one of the finest in Thailand. Four granite pinnacles rising from a sandy bottom at 14–40 metres. Current-rich environment attracts schooling fish (chevron barracuda, jack trevally), and whale sharks visit seasonally (most commonly March–August). Minimum: Advanced Open Water. Recommended: Rescue or Divemaster level for the deeper sections.

Southwest Pinnacle — A cluster of large granite rocks at 18–40 metres. Grouper, trevally, and occasional leopard sharks are resident. Strong current sections but excellent visibility when conditions align.

Sail Rock — Technically accessible from Koh Tao (90-minute boat) but more commonly dived from Koh Phangan. A seamount with a vertical swim-through and consistent whale shark sightings. One of the top sites in the Gulf of Thailand.

Wrecks

HTMS Sattakut — A deliberately sunk 50-metre navy vessel resting at 18–30 metres. Encrusted with coral, populated by lionfish, snappers, and batfish. Accessible to Open Water divers at the shallower end; penetration diving at depth requires Advanced. Good for photography.

HTMS Mataphon — Sunk more recently (2011). Shallower than the Sattakut (10–25 metres) and better suited to beginner divers and snorkellers. Colourful encrustation developing well.

Choosing a dive school

Around 60 licensed schools operate on the island, all PADI or SSI affiliated. The difference between the cheapest and most expensive courses is ฿2,000–3,000 — generally not worth optimising purely on price.

What matters more:

• Instructor-to-student ratio — Maximum 4:1 for Open Water open water phases. Ask directly.
• Boat size — Larger boats are more stable in chop; smaller boats can access more sites. Ask where your course dives will happen.
• Equipment quality — BCD, regulator, and wetsuit should be well-maintained. Request to inspect before booking.
• Night dives — Some schools include night dives in their Advanced package; others charge extra. A night dive on Koh Tao is excellent — octopus, lobster, and sleeping reef fish are all visible.

Established operators (long track record, strong online reviews): Ban’s Diving Resort, Big Blue Diving, Apnea Total, New Heaven Dive School.

Snorkelling without diving

Koh Tao is excellent for snorkelling — the reefs are shallow and the visibility is good. Best snorkel spots:

Shark Bay (Ao Leuk) — The most reliable spot for blacktip reef sharks in shallow water (1–4 metres). Walk in from the beach at the south end of the island. Sharks are non-aggressive and commonly seen in the mornings.

Japanese Gardens — High fish density accessible from the beach or by longtail. A snorkel tour (฿500–700 from the main pier) covers this plus 2–3 additional sites.

Hin Wong Bay — North coast. Good coral coverage accessible from shore. Requires a scooter to reach.

Koh Nang Yuan — The small three-island cluster adjacent to Koh Tao (฿100 entry + ฿100 longtail). The beach between the two inner islands has good snorkelling at the rocky edges.

Costs

Item	Price range
Open Water course (PADI/SSI)	฿9,000–12,000
Advanced Open Water	฿7,500–10,000
Rescue Diver	฿8,500–11,000
Fun dives (per dive, own gear)	฿700–900
Fun dive package (10 dives)	฿5,500–7,000
Snorkel tour (half day)	฿500–700
Snorkel equipment rental	฿100–150