"Iwatobi climbing club" AU
I’m seriously really suprised no one came up with this yet, climbing is basicly vertical swimming and it’s a great sport to do with friends and you get to look at each others butts all the time, winwin! The story would follow the same basic plotline, but all the swimming is replaced by climbing.
They get some new animals too, Makoto is a mountain goat, a steady and strong climber, Nagisa is a cute little squirel who constantly climbs all the trees, and Haruka is a salamander, he climbs incredibly fast and fluent. I once heard that “salamander” is a nickname for incredibly good and dedicated climbers, seems to fit Haru.
I’ll make some more climbing AU soon!