Sri Lanka offers a variety Diving of reef types; coral banks, sandstone platforms and rock cliffs and boulders that are found from near shore to several kilometers offshore. Extensive shallow offshore coral banks occur in Vankalai, Silavathurai and Arippu and along the Kalpitiya Peninsula in the Gulf of Mannar. Diving Coral reefs from the Kalpitiya Peninsula to Negombo are located about 15 kilometers offshore and in deeper water at a depth of about 20 meters. The majority of reefs in the west are sandstone platforms whilst offshore patch reefs similar to those found in Negombo occur off the coast of Colombo between Mt.Lavinia and Galle Face at a distance of about 20 kilometers offshore. Rock boulder reefs Diving are common in the southwestern and southern coasts from Bentota to Tangalle. There are many small fringing coral reefs along the southern coast, the well know coral areas are at Hikkaduwa, Rumassala in Galle, Unwatuna, Weligama, Matara and in Tangalle. In the east coast there are several coral reefs from Nilaveli to the Trincomalee harbor and from Foul Point to Kalmunai located south of Batticola. Reefs from Kalmunai to the Great and Little Basses off the coast of Yala National Park are mainly rock boulder reefs.
Fringing coral reefs Diving are found in the Palk Strait and Palk Bay along the northern and western shores of the Jaffna Peninsula. About 200 species of corals are found in Sri Lanka. Generally they can be classified into five different growth forms; branching, tabulate, foliose, encrusting and massive. Extensive reef formatios such as in the Gulf of Mannar are formed by branching, tabulate and foliose corals. Fish are abundant on most offshore reefs and more than 500 species have been identified. They vary from small damselfish that dart about among coral branches to large parrotfish, jacks and groupers. Sri Lanka has thirty five species of butterfly fish and three species of large angelfish. The best reefs to see large fish are the ones offshore and in relatively remote areas where fishing pressure is low. Sharks are generally uncommon on our reefs and the only area where blacktip sharks can be seen regularly is among the shallow coral reefs inthe Gulf of Mannar.