For the group's 2015 comeback, Sunmi returned to the group, and served as a member alongside Yeeun, Yubin, and Hyerim; the Wonder Girls remained as four-piece band until their disbandment in 2017.
Untuk comeback pada 2015, Sunmi kembali ke grup, dan menjadi anggota bersama Yeeun, Yubin, dan Hyerim; Wonder Girls menjadi grup dengan 4 anggota sampai bubar pada 2017.