Iwabuchi made her debut in the Continental Cup on March 3, 2009 in Zaō and finished in 21st place. At the second jump she was disqualified. On January 23, 2010, Iwabuchi competed in Schonach in the Black Forest, her first jumping outside of Japan and finished 16th. She was disqualified at the Junior World Championships in Hinterzarten . At the end of the 2009/10 season Iwabuchi went to the Continental Cup at the start and finished 15 and 16. In the 2010/11 season , she was there again in Zaō and finished 18th. Since December 2011 Iwabuchi has started several times in the newly created Women's World Cup . At the Junior World Championships 2012 in Erzurum , she won the gold medal in the team competition together with Yūki Itō , Yurina Yamada and Sara Takanashi . In the summer she took 15th place in the overall ranking at the Grand Prix . After the Summer Grand Prix she did not take part in any international jumping for a year and thus skipped the entire 2012/13 World Cup .
At the Nordic World Ski Championships in 2015 in Falun , Sweden , she finished 36th in the individual competition. On February 19, 2016, she reached sixth place in the World Cup competition in Lahti and thus her best career result in an individual World Cup to date. In February 2017 she took part in the Nordic World Ski Championships for the second time in Lahti . With eleventh place she was able to clearly surpass her result of the first participation.
In the 2017/18 season she won the first two team competitions with the Japanese team in the history of the Women's World Cup in Hinterzarten and Yamagata . At the 2018 Winter Olympics in Pyeongchang, she finished twelfth in the individual competition on the normal hill . In the overall World Cup, she finished 16th at the end of the season and achieved the best result of her career to date.
At the 2019 World Championships in Seefeld , she finished sixth together with Yūki Itō, Nozomi Maruyama and Sara Takanashi in the women's team competition, which was held for the first time.
Japan
Hinterzarten
