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 at any time of year; this can be arranged at the Khao Sok National Park Headquarters.
Tham Nam Talu (Nam Talu Cave) is located in the area of the Protection Unit at Kor Sor 4️(Khlong Pae). Traveling by boat from Ban Chiew Lan Municipal Tourist Pier to the Protection Unit at Kor Sor 4️(Khlong Pae). about 1️ hour and then take a boat to the starting point for about 1️5 minutes, walk to the mouth of the cave about 3️ km.