Iriomote & the Yonara Channel

Boat trips run as two- and three-dive excursions. The sites fall into three zones: the north around Barasu Island, the west around Funauki and Amitori, and the south, which takes in Nakano Kamishima and Kanokawa. The Yonara Channel lies between Iriomote and Kohama, the small island to the east. A longer run goes to Ogan, an uninhabited island about 15 km southwest of the southern end of Iriomote and about 1 hour away by boat.

The Yonara Channel is 6 km long and 500 to 900 m wide. Its current is constant and at times very strong, every dive there is a drift, and mantas turn up at several points along it. Kohama, about 16 km around, is surrounded by table and branching coral with tropical fish. In the south, Kanokawa Nakanose is a calm site of lush coral gardens where snappers, mud rays and barracudas school in summer. At Ogan's Eastern Root, huge roots rise from a seafloor at 40 m.

The area suits divers who are comfortable in current, since its namesake channel runs at times very strong and Ogan is an advanced dive in fast current. Divers less sure of drift diving still have the calm southern site of Kanokawa Nakanose, which shares the manta draw. Iriomote lies in Iriomote-Ishigaki National Park, which sits on and around the Yaeyama Islands; it was created in 1972 as Iriomote National Park, taking in Iriomote, Kohama, Kuro and Taketomi, and Iriomote is also a World Natural Heritage site.