Kosei Tani

Gamba Osaka

Born and raised in Osaka, Tani came through the youth ranks at Gamba Osaka and was promoted to the first team ahead of the 2018 season. He made his top team debut in a J.League Cup match away to Sanfrecce Hiroshima on 9 May 2018. Gamba recovered from a 2-0 half-time deficit to run out 3-2 winners. Prior to joining Gamba's J1 team, Tani played 4 times for Gamba Osaka U23 which compete in the J3 League in the 2017 season. Following his elevation to the club's first-team squad, he earned more playing time at J3 level appearing 17 times as part of a rotation system with Ryota Suzuki.

Dender (loan)

On 1 August 2023, Tani signed with Belgium 2nd division club, FCV Dender, on a season-long loan transfer.

Machida Zelvia

On 12 January 2024, Tani was announce official join to J1 promoted club, Machida Zelvia on a loan transfer for 2024 season until 31 January 2025. On 4 January 2025, Tani was announce official permanent transfer to Machida Zelvia for 2025 season. During the 2025–26 AFC Champions League Elite, he was named Best Goalkeeper after recording seven clean sheets, as his club reached the final, where they were defeated 1–0 after extra time by Al-Ahli.

Youth

Tani appeared for Japan as a goalkeeper in the 2017 FIFA U-17 World Cup and played a total of 7 games at that level.

Senior

On 27 July 2022, Tani make his debut for Japan national team playing the full match in a 3–0 win over South Korea during the 2022 EAFF E-1 Football Championship.

Club

As of the start for 2025 season.

Club

Machida Zelvia

Emperor's Cup: 2025 AFC Champions League Elite : 2025–26 Runners-up

International

EAFF E-1 Football Championship: 2022

Individual

AFC Champions League Elite Best Goalkeeper: 2025–26