[3][4] On 6 March 2019, Hashioka made his AFC Champions League debut, at 19 years old, scoring twice in a 3–0 victory over Thai club Buriram United.

[6] Hashioka made his debut in European football on 28 February 2021, as a substitute in a 2–0 defeat to Eupen.

[7] Hashioka joined Sint-Truiden permanently at the end of the season, scoring his first goal for the club on 17 September 2023, in a 2–0 victory over Mechelen.

[8] On 30 January 2024, Hashioka signed with Luton Town, becoming the first ever Japanese player in the club history.

[9][10] He made his Hatters debut after coming off the bench in a 6–2 loss to holders Manchester City in the fifth round of the FA Cup.