This cap works to swim with beautifully. No it is not waterproof, but I hate the tight swim caps, and this is snug but not so tight to be uncomfortable and keeps the hair from getting tangled as it does when I swim without a cap.  I don't mind my hair getting wet if it stays put and does not get tangled and impossible to brush trough.  The design is cute too and the best part is that I was diving to the bottom of the pool for two hours with my grandson to retrieve a rocket and it stayed put.  I had the goggle straps over it so that helped but it stays put for regular swimming anyway.  I am very happy with product but have to say that it is too pricey for something that looks easy to make.  I also exercise with it and it helps keep my hair from flying all over the place and getting in my face.  I imagine it would help to keep the hair from getting messed up at night though it would take some getting used to in order to sleep with it on.