Bali has some of the best diving in the world with warm waters year round, great visibility and an amazing range of tropical sea life. Bump-head parrot fish, green turtles and giant moray are just a few impressive creatures that can be spotted as well as huge shoals of barracuda and even the giant Mola Mola if you visit in the right season.
USS Liberty is the reason most people visit. Hit by a Japanese torpedo in 1963 it is now the most famous dive site in Bali. Stay nearby and dive it early to avoid the crowds. Another great spot nearby is the Buddha statue and coral garden where you can find lots of sunken statues and relics sank by the locals to further encourage the sea life.