Diving Shark Island in Koh Tao, Thailand

Austin Tuwiner
PADI Divemaster · 500+ dives · 20 countries & states
November 6, 2026
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Divemaster Austin at the surface with Shark Island behind him, Koh Tao
Shark Island rising out of the water off the southeast coast of Koh Tao
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I dove Shark Island in August 2026 with Big Blue Diving, by boat out of Koh Tao, Thailand.

It was the last dive of the day, straight after two dives at Sail Rock.

Dive Log · Koh Tao, Thailand · August 2026

Shark Island

Dive Score3.9 / 5
Dive Data from my Garmin Descent MK3i
Max Depth
63ft / 19.3m
Avg Depth
29ft / 8.9m
Dive Time
53min
Water Temp
86°F / 30°C
Visibility
60ft / 18.3m
Entry
Boat
Recommended Certification
Open Water
Why it scored 3.9Tied #4 of 8 I've dived in Thailand
My take: An easy, shallow last dive of the day after Sail Rock. Rays, triggerfish and butterflyfish on the slope, but no sharks for me.
My satisfaction4/5
Marine life4/5
Reef or wreck4/5
Conditions4/5
Crowds3/5
Getting there3/5
My 6 ratings above, plus visibility, water temp, cost, season and ease from the dive data. 5 = calm, uncrowded and easy to reach. How the Dive Score works
Reef Thailand Coordinates: 📍 10.062902, 99.845614

It sits about 3 miles (4 km) southeast of Mae Haad pier, the closest of the sites I dived.

That short run is why it often gets used as the last dive of a longer day.

Big Blue put it at the end of their Sail Rock trip, which is exactly how I dived it.

The Island

Shark Island rising out of the water off the southeast coast of Koh Tao
Shark Island, named for the way the rock sits in the water like a dorsal fin.

Shark Island is a small uninhabited islet off the southeast coast of Koh Tao.

It is named for its resemblance to a dorsal fin, and for its reputation as a hotspot for reef sharks.

The site splits into two experiences.

One side is a shallow coral garden suited to beginners, the other a deeper boulder slope for more experienced divers.

Wide coral garden covering the shallow side of Shark Island, Koh Tao
The shallow side is a wide, healthy coral garden.
The deeper boulder slope running off Shark Island, Koh Tao
The other side drops away into boulders.

Due south and deeper again lies the MV Trident, an ex German coastguard vessel sunk in September 2010 at 36 metres.

That area often sees strong current, which combined with the depth puts it out of reach for most recreational divers.

The Dive

Schooling fish over the rocky slope at Shark Island, Koh Tao
Schooling fish working the rocky slope.

My Garmin logged a max depth of 63 feet (19.3 m) and an average of 29 feet (8.9 m) across 53 minutes.

That makes it the shallowest and longest of my Koh Tao dives.

Blue spotted ribbontail ray resting under coral at Shark Island, Koh Tao
A blue spotted ribbontail ray tucked in under the coral.
A pair of raccoon butterflyfish beside a barrel sponge at Shark Island, Koh Tao
A pair of raccoon butterflyfish beside a barrel sponge.
A large dark triggerfish over the sand at Shark Island, Koh Tao
A large dark triggerfish out over the sand.
A large sea cucumber among staghorn coral at Shark Island, Koh Tao
A big sea cucumber wedged into the staghorn.
A large sea anemone on the reef at Shark Island, Koh Tao
A large anemone on the reef.

I did not see a single shark.

Hard coral and reef fish on the shallow side of Shark Island, Koh Tao
Reef fish over the hard coral on the shallow side.
Reef fish over the coral garden at Shark Island, Koh Tao
Coral and fish along the slope.
Boulder corals and damselfish at Shark Island, Koh Tao
Boulder corals and damselfish.
Staghorn and cabbage coral on the shallow reef at Shark Island, Koh Tao
Staghorn and cabbage coral in the shallows.
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Conditions & Logistics

Visibility on this dive ran around 60 feet (18 m), lower than it typically is at Shark Island.

Water temperature was 86°F (30°C).

Divemaster Austin at the surface with Shark Island behind him, Koh Tao
Back at the surface after the last dive of the day.
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ABOUT THE AUTHOR

Austin Tuwiner

Hey I'm Austin, a PADI Divemaster based in South Florida .

I initially got certified at 16 at a scuba camp in Kona, Hawaii, did my Advanced Open Water on Koh Tao, my deep and nitrox on Gili Trawangan, and my Rescue and Divemaster in Miami.

Since then I've logged 500+ dives across 20 countries and states. I write about the gear I dive with, the sites I've dived, and the trips I've taken.

Hear Austin's Story

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