Crystal Bay is the most famous dive site in Bali and one of the world’s premier locations for encountering the elusive Mola Mola (ocean sunfish), the largest bony fish on the planet reaching over 2 meters in size. Located on the southwest coast of Nusa Penida at the southern end of Ceningan Channel, this small sheltered bay features crystal-clear water with visibility reaching 30-50 meters, the best in all of Bali. The site features a sandy slope starting at 10 meters that descends deeper toward the channel, with hard coral reefs on either side beginning at 5-6 meters. A distinctive rocky island with a temple sits in the middle of the bay. The reef transitions to a steep wall dropping very deep toward the channel where Mola Mola ascend from 20-70 meters to cleaning stations during their season. The site also features an underwater Bat Cave accessible at 20-24 meters where divers can surface inside while bats sleep overhead. Crystal Bay is recommended for advanced divers due to unpredictable strong currents, sudden downcurrents, and cold thermoclines that can occur especially near the drop-off. Besides Mola Mola, the site hosts turtles, reef sharks (wobbegong, leopard, thresher), eagle rays, moray eels, frogfish, banded sea snakes, and abundant tropical reef fish.