Japan
Coral limestone islands between Okinawa and Yaeyama, famous for caverns and tunnels such as Tori-ike and Antoni Gaudi, the vast Yabiji reef complex and clear water off Irabu and Shimoji.
The Miyako Islands lie between Okinawa Island and the Yaeyama Islands. The inhabited islands are Miyako, Ikema, Irabu, Kurima, Ōgami and Shimoji in Miyakojima City, and Tarama and Minna in Tarama Village. The islands are made entirely of coral limestone, and erosion has created many cavern dive sites. At Tori-ike divers swim from the ocean through an underwater tunnel into a freshwater pond; Antoni Gaudi is a cavern named after the architect for its shapes; Satan's Palace is a technical dive through tunnels into a chamber lit in blue. Off northern Miyako lies Yabiji, a group of more than 100 coral reefs. Irabu Island is regarded as a secluded base for divers. Miyako has direct flights from Tokyo and Osaka. Source: Wikipedia, JNTO, Visit Okinawa Japan