Thailand Guide
The deep south
Tham Morakhot: the Emerald Cave
Address: West coast of Ko Mook
Opening time: Closed July– Sept
The stunning "Emerald Cave" (Tham Morakhot), part of Hat Chao Mai National Park, shouldn't be missed. An eighty-metre swim through the cave – 10m or so of which is in pitch darkness – brings you to a hidden lagoon (hong) with an inland beach of powdery sand open to the sky, at the base of a spectacular natural chimney whose walls are coated with dripping vegetation.
The cave can only be visited by boat. Chartering your own longtail boat from Ko Mook is preferable to taking one of the big day-trip boats that originate on Ko Lanta or Pak Meng: if you time it right, you'll get the inland beach all to yourself, an experience not to be forgotten. It's also easy enough to kayak there from Hat Farang on Ko Mook, and at low tide you can paddle right through to the inland beach: buoys mark the cave entrance, from where a tunnel heads straight back into the rock; about halfway along, there's a small, right-hand kink in the tunnel which will plunge you briefly into darkness, but you should soon be able to see light ahead from the hong. Mid-afternoon is often a good time to paddle off on this trip, after the tour boats have left and providing the tide is right.