Following the popular idol group creation strategy of Yasushi Akimoto, girl idol group CGM48 was formed. The name is based on Chiang Mai city situated in Northern Thailand and the color of the group logo represents the lush forest of Chiang Mai.

The formation of the group was announced on the BNK48 event “BNK48 Thank You & The Beginner Chiang Mai” in Chiang Mai. Two members – Punyawee Jungcharoen (Aom) and Rina Izuta (Izurina) – from BNK48 were transferred to CGM48. Among the transferred members, Aom who is originally from Chiang Mai became the captain of the group and Izurina who was previously transferred to BNK48 from AKB48, with 9 years of idol experience, became the shihainin (manager) of the group. After the announcement of the member transfer, auditions for the group was held and first generation members were selected from the audition and was announced.

Through the groups official social media, debut single “Chiang Mai 106” – based on debut song of NGT48 “Maxとき315号
(Max Toki 315 go)” – was announced along with the debut single senbatsu. Sita Teeradechsakul (Sita) was also announced as the center for the debut single.