User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-5020152-20120821215053/@comment-4976561-20120825062157

Sadly, no, JP 3ds will not run EU/US games and vice versa, so you'll need a seccond 3DS for your english games, but I'd say is worth it since is pretty awesome despite the fact that there is no online multiplayer. Besides, you get to keep the JP 3ds for furue releases like MH4 in case they don't get localized at all.