Chicchai Shima no Dekkai Girl

Shigeru, an eighth grader, has moved from the city to a small island. She is dissatisfied and apprehensive about living on the island, which doesn't seem to have any kind of entertainment or anything, but when she finds out that one of her classmates is a girl who's much taller than the school building, she cannot stop her excitement! Big-size Mikuru, Rin (who is the class president by temperament), and Shigeru (the transfer student) are the only three classmates. Though few in number, their every day is stimulating! This slow-life comedy depicts their school lives in a laid-back and amusing way.

(Source: Kodansha, translated)