Itoi was selected to play for Japan national baseball team in the 2013 World Baseball Classic, and started all 3 games as right fielder in the first pool round, batting cleanup in the first 2 games. He is amongst the most consistent batters for Team Japan, getting a hit in each game. During the second pool round, Itoi replaced the ineffective Hisayoshi Chono in center field and continued his batting consistency, hitting a double against Chinese Taipei (Also Team Japan's only second extra base hit up until that moment, with the other also provided by Itoi) and hit a 3-run home run in the mulling of Netherlands. In the semifinal round, however, they lost to upstart Puerto Rico 3–1, thus preventing the team from advancing to the Championship round.
