Kumiko Koga was born in Fukuoka, Japan. She studied clarinet at Musashino Musical College in Tokyo with Masaharu Yamamoto from 1994 to 1998. In 1998/1999, she visited a structure cource of Yoshiaki Suzuki at the Toho Gakuen university in Tokyo. From October 1999 to June 2002, Kumiko studied with Peter Loeffler-Asal, Johannes Gmeinder and Roland Diry (contemporary music) at the University of Music and Performing Arts Frankfurt am Main. In addition Kumiko visited masterclasses with Charles Neidich, Richard Vieille, Ralph Manno and Hans Deinzer.

Kumiko participated in the "Internationale Junge Orchester Akademie" in 2002. Kumiko Koga has played as a solist with the Frankfurter Orchester, Tokyo Philharmonc Orchestra, Kyushu Symphony Orchestra, and Kyushu Chamber Orchestra. The first solo recital was held in Fukuoka in 2002. Kumiko Koga won a prize of DAAD conpetition in 2001. She received the 1st place, honor artistic director's prize and governor's prize from Osaka prefecture at 4th Osaka International Music Competition in 2003. Her first CD "Waldgeflüstr" was released in August 2004. She won the 1st place of the 7th Kyushu Music Competition.

She is a clarinettist of Kyushu Wind Orchestra. Kumiko is also a DJ of a classical music program on KBC radio.