Season 0 of 12-sai.: Chicchana Mune no Tokimeki premiered on April 3, 2014.

Season 1 of 12-sai.: Chicchana Mune no Tokimeki premiered on April 4, 2016.

In Japan known as (12歳. ~ちっちゃなムネのトキメキ~). Base on manga series written and illustrated by Nao Maita. The anime is split into 2 season. Summary: Hanabi Ayase and her best friend, Yui aoi are 6th graders in school. When Hanabi is chosen to work with Yuuto Takao for an upcoming test, she begins to fall in love with him and they both start dating. Yui also falls in love with kazuma Hiyama, after he protects her from a classmate who talked about Yui behind her back, and they start dating as well. But with physiological changes and more and more obstacles in their love lives, will Hanabi nd Yui overcome everything and find true love at the age of 12?

** Opening Theme "Sweet Sensation" by Rie Murakawa.

** Ending Theme "Cotona MODE by AOP (Member: Kei Tomoe, Yuuki Hirose, Saori Ogino, Risa Sakurana, Yui Fukuo and Aoi Mizuki).

Season 2 of 12-sai.: Chicchana Mune no Tokimeki premiered on October 3, 2016.

Continue follow story season 1

Opening Theme "Ano ne, Kimi dake ni" by AOP (Member: Kei Tomoe, Yuuki Hirose, Saori Ogino, Risa Sakurana, Yui Fukuo and Aoi Mizuki).

Ending Theem "Yuuki no Tsubasa" by Machico.