 Muto made his debut for Japan on 5 September 2014 in a 2–0 friendly defeat to Uruguay at the Sapporo Dome, replacing Yusuke Minagawa after 58 minutes.Four days later at Yokohama's Nissan Stadium he scored his first international goal, coming on as a half-time substitute against Venezuela and scoring the first goal of a 2–2 draw six minutes later.As a substitute, Muto played all of Japan's matches at the 2015 AFC Asian Cup in Australia, ending with defeat to the United Arab Emirates in the quarter-finals.