Tanjung Lesung is the perfect spot to begin the underwater exploration of the Krakatau-Ujung Kulon National Park. The national park itself is acknowledged by UNESCO in its World Heritage list because the park contains the largest remaining area of lowland rainforests in the Java plain.
Underwater, divers can expect to see the very rich coral reefs of the Krakatau smaller islands and the coast of Ujung Kulon. The eruption of Krakatau in 1883 had resulted in the presence of underwater volcanic rocks that resemble ancient ruins. These reefs and hard corals upon them are inhabited by some of the richest fish fauna in the archipelago. Numerous reef species, such as butterfly fish, batfish, triggerfish, and moorish idol, dominate the shallower waters, while deep water species include tuna, barracuda and marlin. Sharks and turtles often make their appearance for the lucky divers. Bumpheads and parrot fish are also regulars to the area.