Power outlets in Japan & Korea vs. United States?
Korean and Japanese outlets are the same. However, these outlets are not the same as in the US. Very rarely will you find an outlet with a third prong to protect against a power surge. Almost all outlets have two holes, so make sure you bring an adaptor for that. If it’s a bother, you can find them at electronics stores in Japan. As for voltage, there’s no real difference. Everything works the same. If you plug anything into the wall in America, it’ll work in Japan/Korea. Basically, you have nothing to worry about. Just bring an adaptor if you have something with three prongs.