A wet bag is a waterproof nappy bag for storing used nappies when you are out of the house. They keep liquids and smells in and can be put in the wash with everything else to freshen up. These are useful for: days out, if your child is in daycare, or if you're pushed on space and don't have room for a bucket in the nursery. Some wet bags have a handy dry compartment for clean nappies too. Very handy for swimming costumes, wipes, wet clothes or anything else!