This is a dive site called Onna flats. This is a typical dive site on Okinawa. Boat diving is available here, but isn't all that popular because almost all of the sites are accessable from the shore. Onna is one of my favorite spots to take newly certified divers because of it's ease of access and low difficulty level. The bottom slopes down to around 100ft, but the best diving is around 50ft. It has crevasses and tunnels that make it interesting even for experts. The fish life is also good here, with the occasional sittings of rays. The day this picture was taken most other spots on the island were undiveable due to water conditions. This was shot in late December and the weather was still very good, around 70 degrees.