About 9km northeast of Soppong is Tham Lot (pronounced tâm lôrt and also known as tâm nám lôrt), a large limestone cave with impressive stalagmites, coffin caves and a wide stream running through it for 600m. Along with Tham Nam Lang further west, it’s one of the largest known caves in Thailand, with a total length of 1600m.
Visitors are not permitted to tour the caves alone. At the entrance, you must hire a gas lantern and guide for 150B (one guide leads up to three people) to take you through the caverns. Bamboo rafts (up to three people, one way 300B) from the entrance to the exit take in the Column Cavern, Doll Cave and Coffin Cave. If going one way, you can walk back from outside the cave (20 minutes), but only during the dry season (approximately November to May). In the dry season it may also be possible to wade to the Doll Cave and then take a raft through to the exit (200B). Try to be at the exit at sunset, when hundreds of thousands of swifts pour into Tham Lot and cling to their bedtime stalagmites.
The three side chambers – Column Cavern, Doll Cave and Coffin Cave – can be reached by ladders. It can get crowded on the ladders so watch your step. It takes around 1½ hours to explore the whole complex. During parts of the rainy season (August to October) only one cave is open because of water levels.
A Nature Education Centre has basic displays on the area, as well as exhibits of pottery remains found in the cave.