Phi Phi & the King Cruiser · Thailand · Wall · Cave & cavern · Reef
Koh Doc Mai
A limestone wall running from the surface to 33 m
Area photo: Krzysztof Golik · CC BY-SA 4.0
Koh Doc Mai is a limestone island that soars vertically from the seabed, so the wall starts at the surface and carries on to a maximum of 33 m. Dives are run out and back along the face between 10 and 25 m, with a cave section for those carrying the certification for it. The island sits in a marine reserve 10 km west of Hin Musang.
Also known as Ko Dok Mai, Koh Dok Mai.
Where it is and how deep
7.7964° N, 98.5303° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The island soars vertically from the sea-bed, and that is the dive: a wall that begins at the surface and drops to a maximum of 33 m, worked out along the face and back at normal depths of 10 to 25 m. The current is medium, so which way the wall is worked is settled on the day rather than fixed.
The wall is as much a macro site as a wall. Yellow tiger-tail seahorses hold on to the growth, ornate and harlequin ghost pipefish hang in the crevices, and moray eels and octopus work the holes in the limestone. Turtles come up off the reef, and along the foot of the wall there are leopard sharks, with grey reef sharks and bamboo sharks also on the site.
There is a cave section here, and it is treated as cave diving: the required certifications apply, and without them the dive stays on the open face — no great loss, since the wall itself carries most of the life. Visibility on the site is often 20 m and more, and the island sits inside a marine reserve, 10 km west of Hin Musang.
Marine life and season
- Reef sharks
- Sea turtles
- Octopus & cuttlefish
- Macro critters
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Prime | Prime | Prime | Prime | Good | Fair | Fair | Fair | Fair | Good | Prime | Prime |
Season follows Phi Phi & the King Cruiser: Nov–Apr is the dry season with the calmest, clearest water; the south-west monsoon from May to October brings swell and rain.
Know before you go
- The cave section is cave diving and needs the required certifications; without them, stay on the open face of the wall.
- Medium current runs along the wall, so start the dive into it and keep the return leg with the flow.
Dive videos
Scuba Diving Phuket Koh Doc Mai · LocalDiveThailand on YouTube
Questions divers ask
How deep is Koh Doc Mai?+
The wall runs from the surface to a maximum depth of 33 m. Normal diving depth on the face is between 10 and 25 m.
Can you dive the cave at Koh Doc Mai?+
Only with the right training. The site includes a cave section that calls for the relevant cave certifications; without them, recreational divers stay on the open face of the wall.
Sources
- Koh Dok Mai — Divezone
- Diving in Thailand — Wikivoyage
- Ko Dok Mai (OpenStreetMap) — OpenStreetMap
More dive sites in Phi Phi & the King Cruiser
Pinnacle
The pinnacle the King Cruiser struck, carpeted in anemones
Reef
An easy reef slope and mini wall, also dived from Krabi
Pinnacle
A coral-covered pinnacle east of the Bidas, rarely on the schedule
An 85 m ferry upright on the sand, captain's cabin at 12 m
Swim-throughs behind walls of glassfish, and no current
A wall to 30 m and the soft-coral spur called Finger Reef
Pinnacle
A multi-headed pinnacle off an uninhabited islet, around 15 m
Wall
Underwater cliffs to 21 m, cut by small caverns and swim-throughs
Similar dives elsewhere
Shafts of light in a cracked cavern on the north wall
Caves in a coral wall where whitetips rest up
A wall covered in purple and white soft corals, home to nudibranchs and tiny shrimps
.jpg){kind=link}
A tunnel through the island with three-metre nurse sharks inside