is a railway station in the Koumi Line in the city of Hokuto, Yamanashi Prefecture, Japan, operated by East Japan Railway Company (JR East).
Kai-Koizumi Station is served by the Koumi Line and is 7.1 kilometers from the starting point of the line at Kobuchizawa Station.
The station consists of two ground-level opposed side platforms, connected by a level crossing. The station is unattended.
Kai-Koizumi Station was opened on 27 July 1933 by the Japanese Government Railways. With the privatization of Japanese National Railways (JNR) on 1 April 1987, the station came under the control of JR East.
In fiscal 2010, the station was used by an average of 22 passengers daily (boarding passengers only).