Iwabuchi began her international career in 2008 when she was selected onto the Japan U-17 national team at the age of 15, and participated in the 2008 U-17 World Cup in New Zealand. The team was defeated in the quarterfinals but she was awarded the tournament's MVP (adidas Golden Ball). A French team coach hailed her as a "future star of women's football." Iwabuchi was also awarded the Asian Young Footballer of the Year by the Asian Football Confederation in 2008. She joined the Japan national team for the East Asian Football Championship, held in early 2010, and debuted in the game against China. She scored her first goal against the Chinese Taipei national team in the same competition. In 2011, she played at the 2011 World Cup and Japan won the championship. She played as a substitute in the final against United States. She also played 2012 Summer Olympics and 2015 World Cup. Japan won 2nd place at both tournaments. In 2018, at 2018 Asian Cup, she played full-time in all matches and scored 2 goals. Japan won the championship and she was selected MVP awards. She played 61 games and scored 20 goals for Japan.