Fiji is surrounded by the largest coral reef system in the Southwest Pacific. With an area of 3,869 square miles, there are four major reefs and one major reef system. The major reefs include the outside barrier reef, inside barrier reef and fringing reef at Nameena Island, the Great Astrolabe Reef at Kadavu—also a fringing reef—and the Nuku Reef in the Mamanuka Island Group of Fiji.
A fringing reef is a reef that's close to shore; a barrier reef is a reef that runs generally parallel to the shore, but is separated from it by a lagoon too deep to support coral growth.
Fiji has a significant amount of tourism with the popular regions being Nadi, the Coral Coast, Denarau Island, and Mamanuca Islands. Fiji has a significant number of soft coral reefs, and scuba diving is a common tourist activity. It is the world’s most diverse concentration of reef structures.
According to traveltips.usatoday & wikipedia