Yūki Wakai is a Japanese voice actress and singer from Gifu Prefecture, born on October 30, 1995. She is affiliated with the talent agency 81 Produce and is a member of the voice actress idol group i☆Ris. Her path to the industry began in her second year of junior high school when she entered and won the Avex-sponsored kids' contest Kira Challenge. This led to her attending Avex's training school and, after passing the Avex/81 Produce Anison Vocalist Audition, becoming one of the founding members of i☆Ris in 2012.

Wakai made her voice acting debut in the 2013 anime series Kingdom, performing its ending theme song Destiny Sky, which also marked her solo debut as a singer. Her career became closely linked with the Pretty Rhythm franchise and its successor, PriPara. She voiced Leona West in the long-running PriPara anime series, a role she has reprised in numerous films, stage musicals, and crossover projects, including the 2025 film Aikatsu! × PriPara the Movie: A Miracle Encounter!. Within the same franchise, she also voiced Sara Midorikawa in Kiratto Pri Chan and Yurari Saionji in King of Prism: Shiny Seven Stars. This work was part of a larger trend where she frequently performed alongside her i☆Ris bandmates in these productions.

Beyond the idol-themed series, Wakai has built a diverse portfolio of voice roles. She is known for voicing Itsuki Sumeragi in the psychological gambling anime Kakegurui, Maria von Messina in Wise Man's Grandchild, and Mai Tadakusa in the comedy series Yatogame-chan Kansatsu Nikki. Her casting as Mai Tadakusa, a character also from Gifu Prefecture, was noted as a good match for her background. She also starred as Naoko Naruse in Let's Make a Mug Too, an anime set in her home prefecture of Gifu, and was part of the show's tie-in musical group. Other notable roles include Hikari Jogasaki in Teppen—!!!, Mamoru in My Wife Has No Emotion, and Miharu Kiryu in the 2025 anime Witch Watch.

In addition to her work with i☆Ris, Wakai pursues a solo music career under the name Yuki, writing her own lyrics and music. She released her solo debut single No More in 2021 and held her first solo concert, Hello! My Dream, in 2024. In 2016, she received the Seiyu Award for Best Singing as part of i☆Ris at the 10th Seiyu Awards. She also co-hosts the radio program Takayanagi Akane / Wakai Yuki no Yaodagane with fellow voice actress Akane Takayanagi.