Beautiful Tham Daowadung is rich with rock formations, and bats, crickets and snakes inhabit its eight chambers. There are lights but not stairs; the entrance can be treacherous when wet. A ranger will accompany you in (though it's not required, a tip is deserved). The cave is subject to the park fee and hours.
It’s 6km northwest of the park entrance by road (300B return from the visitor center by túk-túk). Or you can hire a boat (1000B return), but then you’ll have a 1.5km uphill walk to the cave.
Bats stream out of the cave just before sunset, though there are usually very few in the hot season.