Soichiro Kozuki

is a Japanese professional footballer who plays as a winger for Shonan Bellmare.

Club career Kōzuki was promoted to the first team of J2 League club Kyoto Sanga in 2018.

He joined German club 1. FC Düren of the fifth-tier Mittelrheinliga in February 2022.

On 26 August 2022, Kōzuki agreed to join Bundesliga side Schalke 04, where he was initially assigned to the reserve team. However, following his performances in the Regionalliga West, in December of the same year the Japanese player was promoted to the first team and signed his first professional contract in the process, by penning a deal until 2025, with an option for an automatic extension based on a certain number of appearances. He scored his first Bundesliga goal in his second debut against RB Leipzig.

On 30 January 2024, Kōzuki moved on loan to Górnik Zabrze in Poland until the end of 2024, with an option to buy.

On 3 September 2024, 3. Liga club 1860 Munich announced that they had signed Kōzuki. On 26 August 2025, 1860 announced that Kōzuki had left the club after his contract was terminated by mutual agreement. On the same day, he signed with Viktoria Köln, also in the 3. Liga.

On 15 June 2026, Kōzuki returned to Japan and joined Shonan Bellmare.

International career Kōzuki has represented Japan at various youth international levels, having played for all the national teams from the under-16 to the under-19 setup.