A rocky islet off Koh Tao's southeast coast that breaks the surface and drops away to 25 m, so a single dive can use the whole range from the shallows to the base. Current can run hard around the rock, but there is shelter in its lee. The sides carry soft coral and a large school of butterflyfish, and bluespot ribbontail rays are common.
Where it is and how deep
10.0617° N, 99.8449° EPublished position for this site.
The dive
Shark Island is a single rock, and the dive uses all of it. The site runs from the surface down to 25 m, which means a group can take a deep pass along the base early and still spend the back half of the dive circling the shallow rock. Current is the deciding factor on how the dive is run. It can be strong around the island, and the usual answer is to drop on the sheltered side and keep the rock between the group and the flow, which turns a potentially demanding dive into a relaxed one.
The rock carries some of the best soft coral on Koh Tao, and a large school of butterflyfish usually hangs off it alongside the tropical reef fish found across the island's sites. Bluespot ribbontail rays are common, so the deeper part of the dive is worth swimming slowly rather than covering ground. With 25 m at the base and shallow water at the top, the profile stretches easily: work the depth first, then finish shallow in the lee of the island with the safety stop over the rock.
Marine life and season
- Stingrays
- Reef fish swarms
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Good | Good | Prime | Prime | Prime | Good | Good | Good | Good | Fair | Fair | Good |
Season follows Koh Tao: No official closure; whale shark sightings peak March-May and September-October, while October-November bring more rain and surface chop.
Know before you go
- Current can be strong around the island: drop on the sheltered side, keep the rock between the group and the flow, and treat any crossing of the exposed side as a one-way leg.
Questions divers ask
How deep is Shark Island?+
The site runs from the surface down to about 25 m, which is why operators treat it as a versatile dive: a group can take the deeper base first and then spend the rest of the tank on the shallow rock.
Sources
- Shark Island - Scubago — Scubago
More dive sites in Koh Tao
Offshore granite tower where barracuda and jacks school in the blue
Drift
Drift over the Nang Yuan rock, with 40 m a short swim west
Reef
Sheltered fringing reef, sandy bottom at 12 m
Pinnacle
Coral-covered pinnacles beside the Sattakut, 7 m to 22 m
44.9 m navy attack craft, mast at 13 m, seabed at 23 m
Upright navy wreck, superstructure at 18 m, keel at 30 m
Reef
Calm reef in the lee of Koh Nang Yuan, 2 to 16 m
Artificial reef
Sunken jeep and scrap at 10 to 12 m, colonised by reef fish
Similar dives elsewhere
The pinnacle the King Cruiser struck, carpeted in anemones
A current-swept pinnacle from 30 m to within 5 m of the surface
Untouched hard and soft coral on a rock topping out at 8 m
Leopard sharks on the sand under three pinnacles