Since 2017, Hoshino has played on the main Japan Golf Tour. His first win came in September 2018 at the Fujisankei Classic which he won by 5 strokes. With eight more top-10 finishes he finished 2018 as the 6th highest money winner on the tour. Hoshino qualified for the 2018 U.S. Open, his first major, where he missed the cut.