For swim lessons or summertime fun, swim diapers are a must! Ditch those expensive "Little Swimmers" and invest in a swim diaper or two. If you have a young baby, 2-3 is what you need, one to use if they have a bowel movement at the pool, and give you time to wash. If you have an older toddler who doesn't have bowel movements in the pool, one will do just fine. Swim diapers, cloth or disposable, are not meant to contain urine. Don't put your baby in just a swim diaper then drive to the pool, you will have a very wet car seat. Change him before you go in. Public pools are chlorinated heavily to take care of urine, any swim diaper is just meant to contain bowel movements.