[1] Iwai was born in Saitama Prefecture and started playing golf at 8 years old.

Iwai turned professional and joined the LPGA of Japan Tour in 2021.

[1] She had her breakthrough in 2023 when she won three titles and finished second on the money list.

[2] In 2024, she finished top-10 in two LPGA majors, and rose to 26th in the Women's World Golf Rankings.

[5] Her twin sister, Chisato, is also a professional golfer on the LPGA of Japan Tour.