Hiwatashi began skating at age five after a rink opened near his house.[2] He competed on the juvenile level during the 2008–2009 season, placing fourth at the Upper Great Lakes Regional Championships. Continuing as a juvenile in 2009–2010, he won the bronze medal at the Upper Great Lakes Regionals before finishing sixth at the 2010 U.S. Championships. During the 2010–2011 season, he won the juvenile gold medal at both the Upper Great Lakes Regionals and the 2011 U.S. Championships.
In September 2018, Hiwatashi won the silver medal at the 2018 JGP Canada, behind Petr Gumennik. He won another silver medal at his second event, the 2018 JGP Slovenia. These results qualified Hiwatashi to the 2018–19 Junior Grand Prix Final in Vancouver, Canada. He next competed on the senior level at the 2018 CS Alpen Trophy, where he won the bronze medal. Concluding the fall season at the Junior Grand Prix Final, he placed sixth overall after struggling in both programs.
Due to US national champion Nathan Chen's schedule conflicting with the 2019 Four Continents Championships, Hiwatashi made his senior ISU Championship debut after being named to the Four Continents team with Vincent Zhou and Jason Brown. He set a new personal best score and placed eighth.[11]
In his final event of the season, Hiwatashi competed at the 2019 World Junior Championships alongside countrymen Alexei Krasnozhon and Camden Pulkinen. He placed second in the short program, briefly holding the junior world record until it was reclaimed minutes later by Pulkinen.[12] In the free skate, he placed second behind Russian competitor Roman Savosin after cleanly landing a quadruple toe loop-triple toe loop combination but popping a second planned quadruple toe loop to a double toe loop. However, his strong placement in the short program combined with his performance in the free skate allowed him to claim victory overall, and he became the World Junior Champion, ahead of Savosin and bronze medalist Daniel Grassl of Italy.[13]
2019–2020 season
Hiwatashi began his first full senior season with a fifth-place finish at the 2019 CS U.S. Classic. Making this debut on the senior Grand Prix at the 2019 Internationaux de France, Hiwatashi placed tenth in the short program after multiple jump errors but rose to fifth place overall in the free skate.[14]
Competing at the 2020 U.S. Championships, Hiwatashi placed fifth in the short program with a clean skate.[15] Third in the free skate, he won the bronze medal, standing on the senior national podium for the second time.[16] Despite placing third, he was not chosen for one of America's three berths at the 2020 World Championships, the third spot going to reigning World bronze medalist Vincent Zhou, who finished slightly under three points behind Hiwatashi in fourth. Hiwatashi was instead assigned to compete at the 2020 Four Continents Championships in Seoul.[17] He placed ninth at Four Continents.[18]
2020–2021 season
With the coronavirus pandemic raging, Hiwatashi was assigned to compete at the 2020 Skate America, the ISU having made Grand Prix assignments based primarily on geography.[19] Hiwatashi placed fourth at the event, despite a fall and a singled jump in the free skate.[20][21]
In advance of the 2024 U.S. Championships, Hiwatashi was preemptively named to the American team for the 2024 Four Continents Championships, which were to occur in Shanghai the week after the national championships.[30] He finished eighth at the national championships, and then went on to place eleventh at the Four Continents Championships.[31][28]
Skating technique
Unlike most skaters, Hiwatashi jumps and spins clockwise. He also can perform the Biellmann spin, an element rarely performed by men due to the flexibility it requires.[32]
