After the group departed JYP and Big Hit, 2AM was put on hiatus as the members moved to different companies and labels and pursued solo careers.

Following the end of their military service, the group reunited after seven years with their fourth extended play, Ballad 21 F/W (2021).

Along with the members of 2PM, 2AM's Seulong, Jo Kwon, and Jinwoon appeared on the documentary Hot Blood that was aired on Mnet, documented their rigorous training program on their pre-debut days.

Initially, Jinwoon was eliminated on Hot Blood, but he ended up in 2AM due to Daehun's withdrawal from JYPE.

[8] On October 26, 2010, 2AM released their first full-length album entitled Saint o'Clock, with "전활 받지 않는 너에게 (You Wouldn't Answer My Calls)" and "미친 듯이 (Like Crazy)" as the lead singles.

In January 2012 they toured Japan, becoming the first K-Pop idol group to perform at Tokyo Bunkamura Orchard Hall.

[15] The release included the Japanese version of "You Wouldn't Answer My Calls" and a cover Ken Hirai's "Close Your Eyes" (瞳をとじて).

[14] The title track "For You~君のためにできること~" was selected as the theme song for Japanese TBS drama NEO Soumatou Company which premiered on July 16.

In the same year, 2AM held their first Asia concert tour, visiting Hong Kong, Taiwan, Japan and Malaysia.

[17] They recorded a Chinese version of the song "I Wonder If You Hurt Like Me (好痛) while Jokwon expressed some concerns about his pronunciation.

The album, containing nine tracks, is a collaboration with many artists, including pianist & composer Yiruma and Eptione Project.

Members Seulong, Jo Kwon, and Jinwoon all officially switched their contracts back to JYP Entertainment after their contracts with Big Hit Entertainment expired in April, while Changmin stayed with Big Hit due to his involvement with Homme.

Producer Park Jin Young composed several of the tracks, while the title song "Over The Destiny" was written for the group by Cho Kyumin.

[28] Jo stated that, despite his departure from JYP Entertainment, 2AM had not disbanded and that the other members had clauses in their individual contracts which would allow them to promote as 2AM in the future.

[37] 2AM's fourth EP Ballad 21 F/W was announced on October 12, via the groups brand-new Twitter account, set to be released on November 1 by Culture Depot and Stone Music Entertainment.

[42] In April 2010, they participated in the original soundtrack of drama series Personal Taste with a ballad titled "바보처럼 (Like A Fool)",[43] which also became a number one hit.