Japan
A national park island group west of Naha with close to 100 boat dive sites, exceptionally clear and calm water, hard and soft coral gardens and humpback whales in winter.
The Kerama Islands are a group of 36 islands about 32 km southwest of Okinawa Island; Tokashiki, Zamami, Aka and Geruma are inhabited and reached by regular ferries from Naha. Islands and surrounding waters have been protected as Kerama Shotō National Park since 2014, and the Keramashoto Coral Reef has been a Ramsar wetland since 2005, with 248 coral species recorded, mostly Acropora. Close to 100 dive sites are all reached by boat. The group is known for vivid coral seascapes and some of the best visibility in Okinawa, and the calm, clear water makes it especially suitable for beginners. Large sea fans, soft corals and turtles are typical, and humpback whale watching is popular in winter. Many divers visit on day boats from Okinawa Island or stay on Zamami and Tokashiki. Source: Wikipedia, JNTO, Visit Okinawa Japan