Moeka Koizumi is a Japanese actress, voice actress, and singer born on February 27, 1996, in Hyogo Prefecture. She is affiliated with the talent agency Amuse. Koizumi grew up in a musical family, as both of her parents and her grandfather were involved in music-related professions. She has an older sister who works as a model in Osaka under the stage name Licca. Koizumi graduated from university in March 2018 with a degree in broadcasting.

Her path to the entertainment industry began when she won the grand prize in the singing and voice acting category at the Amuse Audition Festival in 2014, which led to her signing with Amuse. She made her debut in 2015 through stage performances.

Koizumi is widely recognized for several major anime roles. She voices Nana Daiba in the Revue Starlight franchise, a role she performs in both the anime series and the stage musicals. In the Love Live! Nijigasaki High School Idol Club series and its related projects including Nijiyon Animation, she plays Shioriko Mifune. She also voices Yuka Jennifer Sasago in the D4DJ multimedia franchise, appearing in D4DJ First Mix and other related anime. Her role as Shiho Ichimura in the critically acclaimed series ODDTAXI and its film adaptation Odd Taxi: In the Woods represents another notable performance. Additional anime credits include Emile in I Shall Survive Using Potions! and Mizuki Fujishiro in Harmony of Mille-Feuille.

Beyond anime, Koizumi has performed in stage productions. She appeared in the stage play adaptation of Yagate Kimi ni Naru (Bloom Into You), playing the role of Nanami Touko.

Alongside her frequent costar Haruki Iwata, Koizumi forms the musical unit harmoe, which is managed by Pony Canyon. The duo's first single, Kimagure Tictack, reached eleventh place on the daily Oricon Singles Chart. Within the Love Live! Nijigasaki High School Idol Club franchise, she also performs as part of the subunit R3BIRTH with her character Shioriko Mifune.

Koizumi's skills include choral singing and the ability to harmonize with a song after hearing it only once. Her hobbies include watching movies and singing a cappella. In February 2022, she tested positive for COVID-19 but was reported to be asymptomatic and focused on recovery under medical guidance.