On July 26, during an E-Girls SHOW event in SHIBUYA-AX, it was revealed that she was one of the winners of the VOCAL BATTLE AUDITION 3 and was added to Flower as a vocalist.

In September 2015 she made her debut as a model in the November issue of the Japanese fashion magazine LARME.

[5][6] On September 20, 2019, with the announcement of Flower's disbandment set for the end of that month, Washio revealed that she would approach her new goal of solo activities while being member of E-girls.

[7][8] On December 22, with the announcement of E-girls' disbandment set for around the end of 2020, it was revealed that Washio would be making her solo debut.

[17] In June 2019 she traveled to California alongside Elly to participate as a guest player in the Fortnite Summer Block Party, a Pro-Am gaming tournament.