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PHUKETYacht Charter

Koh Muk and the Emerald Cave

Ko Mook, Tham Morakot

An eighty metre sea tunnel that you swim through in the dark and come out in a hidden beach inside a collapsed limestone dome.

Hidden beach inside a collapsed limestone dome open to the sky

Tham Morakot is a tunnel at sea level on the west side of Koh Muk. You go in by tender to the entrance, then swim, the last stretch in complete darkness with a line and a torch, and surface inside a circular beach walled by two hundred metres of rock with a disc of sky above it.

It is the single most theatrical stop in the southern Andaman and it takes about forty minutes. The swim is not hard but it is dark, and anyone uncomfortable in water without a visible exit should sit it out rather than find out halfway.

The tunnel is tide-dependent: at high water the headroom at the entrance closes.

Where it sits

PHANG NGAPHUKETANDAMAN SEAMergui, 180 nmAo Po Grand MarinaBoat LagoonRoyal MarinaYacht HavenKoh HongKhao Phing Kan and Ko TapuKoh PanakKoh PanyeeKoh Yao NoiMaya BayKoh Phi Phi DonBamboo IslandRacha YaiRacha NoiSimilan IslandsSurin IslandsRailay and Phra NangKoh Hong, KrabiKoh RokKoh Muk and the Emerald CaveKoh Haa
  • Marina
  • Anchorage
  • On this itinerary
  • Positions are projected from real coordinates. Coastlines are simplified and not for navigation.

Routes that stop here

Source: Hat Chao Mai National Park, Andaman Sea cruising guides. Checked 6 September 2026. Anchorage notes are planning information from cruising guides and operator itineraries, not navigational advice.