Upvote:2
You could contact the local dive shops, and ask them, they would at least tell you where they take you when you take a trip with them.
Tom Sawyer +81 980-83-4677. http://www.ishigaki-tomsawyer.jp/
Hanalee Adventure Tours +81 9031986472. http://hanalee-ishigaki.com/
Umicoza +81 980-88-2434. http://umicoza.com/en/