|Birthday||October 11, 1991|
Koutaro Nishiyama (西山 宏太朗 Nishiyama Koutarou) is a Japanese voice actor who was raised in Kanagawa Prefecture, Japan. He is affiliated with 81 Produce and voices Toru Iwashimizu in the Free! series beginning with Free!-Eternal Summer-.
- Tsuzuru Minagi in A3!
- Minami Natsume in IDOLiSH7
- Kanata Shinkai in ENSEMBLE STARS!!
- Atsushi Kinugawa in BINAN KOUKOU CHIKYUBOUEIBU LOVE!
- Eichi Horimiya in TSUKIPRO
- Ryuuichi Kashima in Gakuen Babysitters
- Yoshiharu Hisomu in KIZNAIVER
- Yuduki Teramitsu in B-PROJECT
- Kazuhito Narita in HAIKYU!!
- Kyosuke Tsuduki in STAND MY HEROES
Outside of the Free! series, Nishiyama has voiced popular characters in a variety of anime, drama CDs and games. Many of these roles have meant working alongside his fellow Free! voice actors, most notably performing character and idol unit songs.
Across the various series this includes, but is not limited to:
- Cross-unit songs with Toshiyuki Toyonaga, Satoshi Hino & Kentaro Kumagai (Asahi Shiina, Nao Serizawa & Aoba Usami's seiyuu) in A3!.
- Cross-unit songs with Toshiyuki Toyonaga (Asahi Shiina's seiyuu) in TSUKIPRO.
- Cross-unit songs with Atsushi Abe & Tsubasa Yonaga (Romio Hayahune & Nagisa Hazuki's seiyuu) in IDOLiSH7.
- Cross-unit songs with Daisuke Ono (Kaede Kinjou's seiyuu) in B-PROJECT.
- Cross-unit songs with Kenji Nojima (Nao Serizawa's seiyuu) in ENSEMBLE STARS!!.