My kids love to play in the water, whether its a pool, a lake, a river, the ocean or even the backyard sprinkler! For these occassions I use swim diapers. The difference between swim diapers and regular diapers is that the swim diapers don't swell up with water like a regular diaper would.
I recently bought Pampers Splashers, which are disposable swim diapers. They are great! I love that they slip on like shorts or pull-up diapers so they are much easier than putting on a regular diaper, especially with a squirmy toddler! The sides do tear away so taking them off is super easy as well. They come in different sizes: small, medium and large. Each size is a different weight range which is printed on the outside of the package, making it easy to find the right fit for your child. They have an elastic type material on the waist and the openings for baby's legs to help them fit right.
We have had an occassional leak or two due to the size range being a bit large, but we have yet to have a "floaty" pop out so I have to say I am happy with these swim diapers!