Iwata was born on January 19, 1954. In June 1981, when she was 17 years old, she was selected the Japan national team for 1981 AFC Championship. At this competition, on June 11, she debuted against Thailand. She played in 2 matches at this championship. In September, she also played against Italy. However Japan was defeated this match by a score of 0–9. This is the biggest defeat in the history of Japan national team. She played 3 games for Japan in 1981.