Kosuke Kitajima
Japan sent a total of 29 swimmers at the London games, after having achieved qualifying standards in their respective events (up to a maximum of 2 swimmers in each event at the Olympic Qualifying Time (OQT), and 1 at the Olympic Selection Time (OST)): Excluding the relay events, eight swimmers competed in more than a single event, including the defending champion Kosuke Kitajima from the breaststroke events.