"Seaside Town Diary") is a Japanese manga series written and illustrated by Akimi Yoshida.

[1] A film adaptation titled Our Little Sister, directed by Hirokazu Kore-eda and starring Suzu Hirose, was first announced in the June 2014 issue of Monthly Flowers.

[3] A spin-off manga series titled Utagawa Hyakkei has been serialized in Monthly Flowers since July 26, 2019.

[4] Umimachi Diary won the Excellence Prize for manga at the 2007 Japan Media Arts Festival.

[20] In 2019, along with Demon Slayer: Kimetsu no Yaiba, Umimachi Diary ranked #10 on the 19th "Book of the Year" list by Da Vinci magazine.