Okinawa does have some of the best diving in the world inlcuding Yonaguni (with an o) which some very old structures- due to some new research the date of these is now up in the air but still very very old- they are now being aged at approximately the same time as much of the ancient Egyptian ruins. Also stand by for some more info on ruins found much closer to the main island of Okinawa- as the dives continue and some mapping is done we will be able to open this site soon I hope.
The US military does have 3 dive centers on Okinawa - for exclusive use by US military personnel and those over here supporting them- for others out in town will have to do. English can be a problem when you leave the bases but you can definately get by at most places on Okinawa. There are numerous dive shops and resorts on the island and a few including Reef Encounters (which I own) that cater to English speaking clientele as you move south to Yonaguni this is more rare. Ishigaki has Umicoza and we run trips to Yonaguni and other islands. The diving is definately world class over here and we would like to invite you all out to see it. You can cruise our web page for more info of help arranging a trip, or if you just want to see some cool photos of the area.
(and the first white guy to dive the ruins definately doesn't run a dive shop on a US military base- although it makes a good story)