So, I know dogs can swim. However, my river has huge currents and strong ones, these make me very nervous. I almost lost my dog in there because she got tired swimming against the current. She finally made it back to shore, but I decided that wasn't going to happen again. I got her this life vest and it works like a charm! She still funs out and chases the floaties, and swims back with them, the difference is she doesn't tire out as easy and when she does I know she will still be afloat. Also when we take her in the boat with us, I know she is safe! It is well constructed and very bright, so you can see the dog in it from a distance. It fit my 85 pound black lab perfectly!