Sahomi Koyama is a Japanese voice actress known for her work in anime and video games, with a career active since the mid-2000s. She was born on February 27 in Hiroshima Prefecture, has blood type B, and a height of 158cm. Her career began under a different stage name, Saho Ito, as a member of the agency Azlead Company. She later changed her name to Chihiro Umehara and moved to TAB Production. After a period as a freelancer, Koyama adopted her current stage name, collaborated with AZ creative, and has operated as a freelance voice actress since 2021.

Koyama is best known for her role as Zhang Bao (Chouhou) in the anime series Shin Koihime Musou, which aired from 2009 to 2010; she reprised this role in the 2011 OVA Shin Koihime Musou: Otome Tairan OVA Special. One of her most prominent recent roles is Shizuku Mizuori in the Summer Pockets franchise. She first voiced the character in the original 2018 visual novel and its subsequent versions, and she returned to the role for the television anime adaptation premiering in 2025.

In addition to these roles, her extensive voice work in video games includes Kanako Toyoharu in Hakare na Heart (2007), Yoko Serizawa in Fuurai Kiki 2 (2005), and roles in titles such as ChuSingura46+1, Nanairo Reincarnation, Moe Moe 2-ji Daisen, Silvario Trinity -Beyond the Horizon-, Oreyome, and We Should Fuku! Triangle. Beyond voice acting for anime and games, Koyama has also worked as a narrator for commercials, including for Mitsui Fudosan, and for educational materials. She has performed in stage productions with theatre companies such as 975hpa and the Kakashi company. She has also participated in musical projects, performing character songs related to the titles she has worked on. While she has not received major publicized awards, Sahomi Koyama has built a solid reputation through consistent and versatile performances across multiple media, earning appreciation from fans of the various franchises she has contributed to.