Tham Nam Thalu

Reached on foot from the southwestern shore of Chiaw Lan Lake, Tham Nam Thalu contains striking limestone formations and subterranean streams. It is only partially accessible during the rainy season and we don't recommend visiting then; there have been fatalities due to flash flooding. You'll need a guide (per day 1200B) at any time of year; this can be arranged at the Khao Sok National Park Headquarters.