As coach Kei Hosoya (細谷 圭, born January 17, 1988) is a Japanese former professional baseball infielder who is currently a coach for the Toyama GRN Thunderbirds of Baseball Challenge League.

He has played in his entire career with the Nippon Professional Baseball (NPB) for the Chiba Lotte Marines.

[1] On April 13, 2008, Hosoya made his NPB debut.

[3] On December 26, 2020, Hosoya announced his retirement and also become coach for the Toyama GRN Thunderbirds of Baseball Challenge League.

[4] This biographical article relating to a Japanese baseball infielder is a stub.