On May 23, 2012, Sakai debuted for the Japan national team against Azerbaijan. He battles with Atsuto Uchida for right side back. In July 2012, he was selected the Japan U-23 national team for 2012 Summer Olympics. He played 4 matches and Japan won the 4th place. In 2014, he also participated 2014 World Cup, but he did not play in the match. From 2016, he played many matches instead Uchida who injured. In 2018, Sakai participated 2018 World Cup. He played all 4 matches and Japan qualified to the knockout stage. In 2019, he also played at 2019 Asian Cup and Japan won the 2nd place.