Tham Nang Aen Cave is located 18km northeast of Thakhaek on Route 12. To get into this cave, you need to turn right at the sign and go 700m along the access road, fording a small river along the way. If the river is flooded you can cross using the small foot-bridge. Restaurant facilities are available in the dry season. There is small entrance fee.
The legend of this cave is linked to Tham Xienglieb Cave. The story goes, that Xieng, the young former novice who went looking for the beautiful daughter of the hermit at Tham Xienglieb Cave, met with her at the entrance of this cave. Here the two lovers sat (meaning nang in Lao) and flirted (aen kan). Hence the name Tham Nang Aen (Cave of Sitting and Flirting). This cave is a favorite weekend destination for Lao and Thai people and is a great place to cool off from the heat because of the cave's natural air conditioning, there is a constant cool breeze blowing out of it. The cave is up to 30m high in some places and over 1.5km long. It contains a small underground lake and impressive limestone formations. The cave is well lit and cement walkways and steps have been constructed for your safety. The large cave entrance is accessed through a wooden ceremonial structure built in 1987 for the visit of the Princess of Thailand. On the grounds just outside the cave is a simple zoo with severall animals and a very large Mai Kaphoung tree (Tetrameles nudiflora).