Riko Hirai is a Japanese voice actress and singer from Osaka Prefecture, born on March 25. She is affiliated with the talent agency Kenyu Office. Her career began in the early 2000s, and she is known for her work in both anime and video games, particularly in adaptations of visual novels. She also has a parallel career as a singer and lyricist under the stage name Rita, while using Riko Hirai for her voice acting roles.

Hirai made her debut as a voice actor in 2004, providing the voice for the character Nin'i-tan in the original video animation Netrun-mon the Movie. One of her most prominent and long-running roles is that of Latooni Subota in the Super Robot Wars Original Generation series. She has voiced this character across multiple animated adaptations, including the television series Super Robot Wars OG: Divine Wars and Super Robot Wars OG: The Inspector, as well as the original video animation Super Robot Wars Original Generation - The Animation. This role is widely considered her most representative.

Her other notable anime roles include Hikari Tsukishiro in the 2002 original video animation Wind: A Breath of Heart and its subsequent television series. She also voiced the character known as A-chan Senpai in the original video animation Kud Wafter and its related television series, including an appearance in the crossover series Kaginado. Beyond these, her filmography includes the role of Corticarte Apa Lagranges in the video game adaptation of Shinkyoku Soukai Polyphonica and Nanaka in the game Cross Channel.

In addition to her character work, Hirai has contributed musically to several of the projects she has been involved with. For the Super Robot Wars Original Generation series, she performed the character image song Fairy Dang-Sing, which was used as an insert song in the anime Super Robot Wars OG: The Inspector. She was also responsible for performing the theme songs for the visual novel Little Busters!, on which her stage name, Rita, is credited. Her vocal work is a significant part of her career, and she has released multiple music albums. As a voice actress, she is recognized for her distinctive husky voice and her ability to portray a wide range of characters.