Capt Grumby,
I'm not stationed in Korea, but have been there quite a few times. I really liked the Osan AFB area. There is a lot of shopping and bars. Chinhae, I could live without, Pusan was cool. I believe that is where you can get your diving in. Donghae was ok. From a visitor’s point of view, diving is hard. As I posted before, I have had a hard time getting in the water in Korea. The cool think being over here is we are so close to other great dive spots like the PI, Saipan (well Micronesia in general) Okinawa, a bunch of dive spots. If you are into tech, a lot of guys I have spoke to do most of their deep stuff in PI. This is coming from tech shops in Hong Kong and Malayasia.
It really is awesome being stationed on this side of the world. I'm lucky because I'm Navy so I get a free ride to all the spots, but the logistics can be a pain in the neck in less popular dive spots like HK, and Korea. I'm sure from a local’s perspective you can get your diving on in Korea with no problem. Like us guy around Kanagawa we know that not all the diving is in Izu for main land Japan. Good luck, I hope some local ROK folks hit this up.
When do you plan on making your way to our side of world? I would love to have a contact here. If you happen to take orders to Yokota hit me up. I know the club there is pretty active (from what I hear) but I think they do most of their diving in Izu. I am looking to make it out the lakes of Fuji real soon, and I dive some "free" spots around Yokohama.
PacChill