Iwakawa made her professional debut on 19 December 2011, where she defeated Shoko Hayashida by knockout KO in a four-round bout at the Korakuen Hall in Tokyo.
[2] Iwakawa went on to amass a 5–4–1 record over the next five years, before being booked to face Narirat Klaphom for the vacant OPBF female light flyweight title on 20 August 2016.
Iwakawa fought the #1 ranked WBO flyweight to stay busy, as she had been out of the ring for 17 months, with her previous bout against Nao Ikeyama taking place on 29 July 2018.
[9] Iwakawa made her first WBO atomweight title defense against Nanae Suzuki on 26 September 2020, at the Central Gym in Kobe, Japan.
[19] Iwakawa lost the IBF World title to fellow Japanese boxer Sumire Yamanaka with a unanimous decision defeat at Korakuen Hall in Tokyo on 12 January 2024.