Japan
Japan's southwestern archipelago around Ishigaki and Iriomote, known for year-round manta ray cleaning stations, pelagics at Nakano-ogan and winter hammerhead schools and the Underwater Ruins off Yonaguni.
The Yaeyama Islands are the southwestern group of the Ryukyu chain, with Ishigaki, Iriomote, Kohama, Taketomi, Kuroshima, Hateruma and Yonaguni among the inhabited islands. Much of the area belongs to Iriomote-Ishigaki National Park, founded in 1972 and extended to Ishigaki in 2007. Ishigaki is dotted with manta ray cleaning stations, so mantas can be seen all year; Kabira Ishizaki Manta Scramble, Manta City Point, Yonara Channel between Kohama and Iriomote, and Panari Big Corner are the best known. Near Iriomote, Nakano-ogan has about 50 dive sites with schooling pelagic fish and chances of whale sharks. Yonaguni, Japan's westernmost inhabited island, draws divers from winter to spring for schools of hammerhead sharks at Irizaki and the rock formation known as the Underwater Ruins; currents there require advanced skills. Source: Wikipedia, JNTO, Visit Okinawa Japan