The Story of the First Time at Sea with Friends
Noticing Futaba struggling with strength, Mato has her and Hikari go jogging to build up strength. Along the way, they come across some students from diving school, Ai and Makoto Ninomiya, who turn out to be their upperclassmen in the Diving Club. After a hectic first meeting, Ai holds a meeting to discuss how Futaba will be aiming for an Open Water Diver Certification, which somehow ends in a chalk drawing session.
Aired 05/08/2016EP 5 - The Story of the First Time at Sea with Friends

Amanchu!
Hikari Kohinata is an overwhelmingly cheerful and outgoing 15-year-old girl who has spent all her life in a small and beautiful seaside town on the Izu peninsula. On the first day of high school, she meets Futaba Oki, a slightly introverted girl who has just moved from Tokyo. Before she knows it, Futaba gets dragged along into Hikari's passion for scuba diving. And from there, Futaba gradually starts to come out of her shell, and learns how to take challenges and dive into the ocean of life.
(Source: Anime News Network)