All the new models should work there. The big stumbling block is your plan, as this determines what you can do there. For me, on a cheap, shitty LG plan on an equally shitty Anycall
GlorMagic Hole handset, I was able to receive calls and messages in roaming mode. However, I was unable to make outgoing calls, unless they were directed back to Korea. Thus, using the handset in country was impossible. Hypothetically, if I had a International Calling Card purchased in Korea on me, I may have been able to dial that number, then enter a local number and route a call from Japan to Japan via Korea in case of trouble. I dread to think of the cost though.