On 17 January 2020, Kotaro joined Albirex Niigata for the upcoming 2020 Singapore Premier League season.
He helped the club to win the league title at the end of the season.
On 12 January 2021, Kotaro returns home to joined fourth tier of Japanese football club, Tiamo Hirakata which is playing in the 2021 Japan Football League.
On 20 March 2021, he make his club debut against MIO Biwako Shiga.
This biographical article related to a Japanese association football defender born in the 1990s is a stub.