MV Trident Wreck, Koh Tao: Depth, History & Diving

The MV Trident wreck is one of the few true wreck dives around Koh Tao, and one of the hardest to reach. She lies on the sand off the south-east corner of the island, just beyond Shark Island, at around 34 to 36 m. That is below the recreational limit, so this is a dive for nitrox-certified, deep-trained or technical divers.

The Trident is a lesser-known site, and we would rather say so than oversell it. Most visitors to Koh Tao never dive her. If you do, expect a straightforward steel wreck on an open seabed, a short bottom time and a long, careful ascent.

MV Trident dive site map

1MV Trident, about 24 m long, 36 m
2Shark Island, about 300 m north

Usual route: Descend the shotline onto the wreck, tour the hull and structure with limited bottom time, then ascend with decompression and safety stops. Drawing based on local dive briefings: approximate, not to scale and not for navigation. Your guide's briefing on the day always comes first.

History of the Trident

Before she was a wreck, the Trident was a working boat with a real story. She was a converted former patrol boat, about 24 m long, and she became the first technical-diving liveaboard based on Koh Tao. A British expat team used her to search the Gulf of Thailand for wrecks nobody had dived before.

When a larger boat replaced her, the owners stripped out the valuable equipment, cleaned the vessel and sank her on purpose as an artificial reef. That happened in September 2010. Because she was prepared before sinking, she is a clean wreck rather than a cluttered one.

Diving the Trident wreck, Koh Tao

The usual plan is simple. Drop down a shotline to the wreck, tour the hull, deck and bridge structure with limited bottom time, then make a slow ascent with the decompression and safety stops your plan calls for.

She rests on sand at 34 to 36 m, so the seabed around her is flat and open. There is not much shelter from current down there or at the surface, which is why gas planning and a surface marker matter more here than on almost any other Koh Tao dive.

What to expect underwater

Do not expect a heavily penetrable wreck. She was cleaned and stripped before she went down, so the interest is the shape of the ship itself: the hull, the deck and the bridge, set against the sand. Exact details like the height of the wreck above the seabed and how she lies change with the tide and where you measure, so ask your guide at the briefing.

Marine life here is not well documented, and we will not guess at it. As with any wreck, it tends to gather fish over time, but the draw is the history and the technical challenge, not a wildlife checklist.

Conditions and who can dive it

Currents here are often strong, and the site is exposed. The dive can be cancelled on the day if the water is not right, so keep your schedule flexible.

Who: nitrox-certified, deep-trained or technical divers.
Training: used for entry-level technical dives and wreck specialty courses for divers who already hold the right deep and nitrox certifications.
Not suitable for: snorkellers, shore access or casual recreational divers.