HTMS Suphairin Wreck, Koh Tao: Depth, Map & History

The HTMS Suphairin is a former Royal Thai Navy fast attack craft that now rests off the west coast of Koh Nang Yuan. It was sunk in September 2023 to create an artificial reef, and since then it has become one of the most talked-about wreck dives around Koh Tao. You may also hear it called Suphairin 313 or the Noname wreck.

The ship sits upright on sand, with its mast and bridge rising to about 16 m and the seabed at 24 to 28 m. It lies only about 15 m from No Name Pinnacle, so most dives combine the two. It is Advanced territory, and a very good introduction to wreck diving.

HTMS Suphairin dive site map

2Suphairin hull, top 16 m
3No Name Pinnacle, top 14 m
4Mooring (approximate)

Usual route: Descend the mooring to the wreck's upper structure at about 16 m, tour deck, bridge and mast, then drop to the sand edges before finishing on No Name Pinnacle. Drawing based on local dive briefings: approximate, not to scale and not for navigation. Your guide's briefing on the day always comes first.

Diving the HTMS Suphairin: the route

You descend the mooring to the upper structure at around 16 m, then work your way around the ship. Swim along the deck, look at the bridge and the mast, then drop down to the sandy edges at 24 to 28 m to see the hull from below.

When your gas or time says it is time to come up, swim over to No Name Pinnacle for a shallower finish on its rocks, or simply start your safety stop on the mooring.

Because the wreck is so close to No Name Pinnacle, the Suphairin on its own rarely makes a whole dive plan. Think of it as one stop in a two-site outing: wreck first while you are deepest, then rocks and shallower water. Check with your centre which order they prefer on the day, as the tide and the current decide it.

Underwater layout

The hull measures about 45 m by 7 m. The mast, bridge, deck and weapon mounts are all still there, including a gun on the bow and a machine gun mount at the back. Before sinking, the crew cleared access points and reinforced the doorways so divers can move around safely.

Penetration is for divers with wreck training only. The ship has been prepared with care, but a hull is still an overhead environment, and it is not a place to improvise. Sand around the wreck is home to resting rays, and No Name Pinnacle stands about 15 m to the south-east.

Marine life at the Suphairin

The wreck is young, so the reef is still growing in. Corals, hydroids, bryozoans and soft corals are settling on the steel.

Patrolling fish: yellowtail and chevron barracuda, trevally, snapper, Malabar grouper, fusiliers and sweetlips. Great barracuda show up at dawn and dusk.
On the sand: Jenkins whiprays and blue-spotted ribbontail rays.
Small stuff: cleaner shrimp, Durban dancing shrimp, nudibranchs, butterflyfish, angelfish and triggerfish.

Because the ship is still new, what lives on it changes quickly. Return a few times and compare how the encrusting growth fills in on the rails, the mast and the gun mounts.

History of the wreck

The ship was built by Singapore Shipbuilding and Engineering and entered Royal Thai Navy service in the mid-1970s, as a sister ship of the HTMS Hanhak Sattru. After about 42 years of service it was decommissioned in 2018 and handed to the Department of Marine and Coastal Resources for its Underwater Learning Park and Marine Ecosystem Rehabilitation Project.

Around five years of preparation followed. The fuel was drained, hazardous materials were removed and doorways were cleared. In September 2023 she was sunk west of Koh Nang Yuan. Her sister ship went down the same month at Aow Mao, on the east coast. The Suphairin is the first new west-coast wreck since the HTMS Sattakut in 2011.

Conditions and best time to dive

Visibility is usually about 15 to 25 m, which is good for a wreck. Current is typically mild but can strengthen around the biggest tidal exchanges, so keep an eye on it. March to September tends to be the best window. In winter the west coast can get swell, and from June to August monsoon waves may make the surface rough.

The surrounding sand makes for a clean, open backdrop, so the wreck often looks sharp in photos when the water is clear.

Tips from local divers

Bring a torch for the shaded corners of the ship.
Go early or late in the day if you want to see the great barracuda.
Combine the wreck with No Name Pinnacle in a single dive.
Only enter the hull with proper wreck training.

Safety notes

You are diving to as much as 28 m, so narcosis and short no-decompression limits apply. Check the current before you descend, and expect west-coast swell in winter. Stay outside the ship unless you are trained and equipped for penetration.