Oops, it doesn't look like 'swim day' is a national day..

Other days

youth

Youth Day
boyfriend

Boyfriend Day
comfy

Comfy Day
eat what you want

Eat What You Want Day
cuddle up

Cuddle Up Day
pick me

Pick Me Day
frozen yogurt

Frozen Yogurt Day
bow tie

Bow Tie Day
me

Me Day
camera

Camera Day