On May 31, 2000, Otani debuted for the Japan national team against Australia. She was a member of Japan for 2003, 2007 World Cup and 2004 Summer Olympics. She scored a hat trick in Japan's victory over Argentina in the 2003 World Cup. She also played at 2001, 2003 AFC Championship, 2002 Asian Games and 2006 Asian Cup. She played 73 games and scored 31 goals for Japan until 2007.