Koyama Rio (小山梨織) is a former member of NICE GIRL Project! as a NICE GIRL Project! Kenshuusei. She joined on March 18, 2012.
Her last blog post was on November 8, 2013. Several months later in March 2014, she appeared in a photo on Ueno Suzuka's Twitter, where Ueno mentioned that Koyama was a former NICE GIRL Project! Kenshuusei.
- Name: Koyama Rio (小山梨織)
- Nickname: Mario (まりお)
- Birthdate: October 14, 1995
- Birthplace: Tokyo, Japan
- Bloodtype: A
- Her favorite subject is world history.