The blue lagoon at the base of the cliff is the most photographed spot in Vang Vieng, and on weekends it fills up. Rope swings hang from trees at the water's edge. The swimming is excellent — the water stays cool and clear, and the karst backdrop makes the setting feel almost theatrical. After a swim, the climb up to the cave takes about 20 minutes on a steep path; wear shoes you don't mind getting muddy.
Getting here requires a tuk-tuk or bicycle ride of about 6 kilometres west of town, followed by a walk across a bamboo footbridge over the river. The approach through farmland and past smaller pools is pleasant. The entrance fee covers both the cave and the lagoon.