Hiyu Yamakoshi joins Hillspeed for selected GB3 rounds in 2025.

Tokyo’s Yamakoshi is also racing in the Formula Regional European Championship by Alpine (FRECA) this year and has two seasons of Formula 4 experience under his belt within Europe.

Beginning his motorsport career in karts, Yamakoshi won his domestic SL National Championship in 2019, was runner-up in the All-Japan FS125 Karting Championship the following year and then also second in the SL National Championship. Additionally, he finished second in the IAME Japan Series X30 Junior Championship in 2020 and he went on to compete in the CIK-FIA European Championship.

Debuting in cars in Formula 4 in 2023 as part of the F4 UAE Championship, the Japanese racer then dovetailed campaigns in Europe that same year in the French F4 Championship and the F4 Spanish Championship – achieving five podiums in the former.

Remaining in F4 last year, Yamakoshi was third overall in the Italian F4 Championship with two wins and he was also a double winner in the Euro 4 Championship, in which he was fourth in the standings. This year, the teenager has already made outings in the Formula Regional Middle East Championship. 

Career history:

2025
Formula Regional Middle East
Formula Regional European Championship

2024
Italian F4 - third overall with two wins, three poles, three fastest laps and seven podiums
Euro 4 Championship - fourth overall with two wins, one fastest lap and four podiums
Formula 4 UAE
F4 Spanish Championship

2023
French F4 - fifth overall with five podiums and two fastest laps
F4 Spanish Championship 
Formula 4 UAE