An unlit limestone cave in the middle of Lanta Yai, entered only with a local family guide: a 20-30 minute forest walk, then ladders, tight squeezes and a cold pool at the bottom. About 300 baht and 2 hours; wear shoes that can get muddy.
Muay Thai camps around Koh Lanta
Other stops in Koh Lanta
Klong Toab, Krabi, Koh Lanta