LONELY TUNING is a bonus CD sung by AZALEA, a sub-unit under Aqours. The group consists of Matsuura Kanan, Kurosawa Dia, and Kunikida Hanamaru. The CD is a bonus for purchasing the entire Love Live! Sunshine!! Season 1 Blu-rays from Sofmap (ソフマップ).
The song is written by Hata Aki, composed and arranged by Kon-K.