[1] After attending Waseda University, Kojima joined Oita Trinita in October 2018 for the 2019 season.

Kojima made his debut for Albirex on 23 February 2020, playing the full 90 minutes as they beat Thespakusatsu Gunma 3-0.

[4][5] In May 2019, Kojima received his first call-up to the Japan senior national team by head coach Hajime Moriyasu, being included in the final squad for the Copa América in Brazil.

[6] In October 2023, he was called up again to the Samurai Blue squad, replacing injured Daiya Maekawa, for two friendly matches against Canada and Tunisia.

This biographical article related to a Japanese association football goalkeeper is a stub.