Ranked third in the short and first in the free, she outscored Russia's Alisa Fedichkina by 0.42 for gold at the JGP in Logroño, Spain.

In November, Shiraiwa won the silver medal at the 2015-16 Japan Junior Championships behind Wakaba Higuchi.

Making her debut at the Japan Championships on the senior level, she placed 5th, and was named as a member of the Youth Olympic and the Junior World teams.

[1] Making her senior international debut, Shiraiwa won the silver medal at the Asian Open Trophy.

Debuting on the senior Grand Prix series, Shiraiwa finished eighth at the 2017 NHK Trophy and sixth at the 2017 Internationaux de France.

[1] Competing on the 2019–20 Grand Prix series, Shiraiwa placed ninth at the 2019 Internationaux de France and tenth at the 2019 Rostelecom Cup.

[7] Following the season, Shiraiwa left longtime coach Mie Hamada to train under Takeshi Honda.

[7] Shiraiwa announced her intention to sit out the 2022–23 figure skating season in November to "physically and mentally recharge.