Kenkou Zenrakei Suieibu Umishou, Amanchu! Recommendations
Cheerful and quirky heroine; group of highschoolers being into water sports; likable design; comedy
The most notable connection between these two shows are the green haired main characters - free spirited airheads almost to the point of being annoying. But in the end they're everyone's friend.
Don't forget about swimming and the sea! Amanchu has a swimming club; Umisho a swimming club. A lot of splashing around happens in the ocean. However, Umisho is more focused on comedy and pervy scenes whereas Amanchu on friendship and slice of life.