Naha is the main city but is not a an great overall location to stay if you’re diving Okinawa. It’s an hour to an hour and a half south of the majority of the dive sites on the island. Naha IS however a good launching point for Keramashoto National Marine Park.
Itoman is closer to the sites in the south. The southern sites tend to be much more advanced with some stiff currents, but people boat dive them.
Onna is really well placed and is much closer to the best dive sites on the main island. Onna is about an hour to an hour and a half from Naha. It’s a beach tourist town with guides/charters a plenty.
Sunabe/Mizugama have a lot of dive shops and dive hotels and is also better placed than Naha. They have several shore dive sites, but not really great boat launch sites
Chatan and Ginowan are better placed than Naha and are good boat launching sites for Keramashoto. American Village is in Chatan and is super popular with tourists, but you’re also in the central location for the largest military bases so there’s a lot of airmen and marines running around there. The traffic is really bad too.
Further north of Onna is a larger city called Nago. Nago is where the aquarium is (I highly recommend a morning or afternoon at the aquarium if you’re going to visit). Nago is closer to more northern dive sites, but Onna would probably be a better place to stay.
