LOONA 1/3 (Hangul: 이달의 소녀 1/3), stylized as LOOΠΔ 1/3, is the first sub-unit of the girl group LOONA. They debuted with members HeeJin, HyunJin, HaSeul and ViVi on March 12, 2017 on Inkigayo with their song "Love & Live".
01. Heejin (희진): born in October 2000. Introduced in October 2016. Her animal is a rabbit and her colour is bright pink.
02. Hyunjin (현진): born in November 2000. Introduced in November 2016. Her animal is a cat and her colour is yellow.
03. Haseul (하슬): born in August 1997. Introduced in December 2016. Her animal is a bird and her colour is green. She is the unit's leader as well as the entire group.
04. Yeojin (여진): born in November 2002. Introduced in January 2017. Her animal is a frog and her colour is orange. Represents the slash in 1/3.
05. ViVi (비비): born in December 1996. She is the only Chinese member. Introduced in February 2017, but her representing month is April, due to her single being released during that month. Her animal is a deer and her colour is pastel rose.