Koichiro Koga (古賀 幸一郎, Koga Kōichirō, born (1984-08-30)30 August 1984) is a retired Japanese male volleyball player. He was a part of the Japan men's national...

Keitaro Koga (古賀 鯨太朗, born 1991), former Japanese footballer Koichiro Koga (古賀 幸一郎, born 1984), Japanese volleyball player Makoto Koga (古賀 誠, born 1940)...

Kimura (木村 浩一郎, 1969–2014), Japanese mixed martial artist Koichiro Koga (古賀 幸一郎, born 1984), Japanese volleyball player Kōichirō Matsuura (松浦 晃一郎, born...