Mari Doi is a Japanese voice actress born on November 11 in Oita Prefecture, Japan. She is affiliated with the talent agency EARLY WING, having moved there in April 2025 following the closure of her previous agency, Office PAC. Her height is 153cm. Known for her versatile vocal range, she performs in anime, video games, and dubbing for foreign films and television series. Her skills include traditional Japanese dance, kyogen (a form of comedic theater), and playing the flute.

Doi is recognized for her role as Mila Babicheva in the sports anime series Yuri!!! on ICE. She also voiced Octavia in the dark fantasy series Garo: The Animation (also known as Garo: The Carved Seal of Flames). Her other notable anime roles include parts in Violet Evergarden, where she voiced characters such as Ibelis Konoe, Iris's aunt, and a landlady; the teacher in Call of the Night; the narrator in The God of High School; as well as roles in Devilman Crybaby and Cheer Boys!!. In the world of animation film, she has appeared in Inu-Oh, Penguin Highway, and Lu Over the Wall.

Her video game work is extensive, most notably as the Japanese voice of the character Valkyrie in Apex Legends. She has also contributed to major franchises, including Final Fantasy VII Remake, Lightning Returns: Final Fantasy XIII, Kingdom Hearts III, Granblue Fantasy, and YU-NO. In the field of dubbing, she provides the Japanese voice for international actors in Hollywood productions, including Jurassic World, Wonder Woman, Jumanji: Welcome to the Jungle, Maleficent, and the Fantastic Beasts film series. Beyond voice work, she has experience on stage, having performed in productions such as California Dreamin' and Shakespeare's The Comedy of Errors.