All-In-One nappies have an outer wrap that is permanently attached to an absorbent inner nappy, making only one piece to put on.  These nappies are designed to match the convenience of disposable nappies and they do score highly in this area as they are quick and easy to put on with elastication at the legs and waist giving a snug fit.

Because the nappy and wrap are 'one peice', all-in-ones are slow to dry compared to other nappies, although some are now being made with lightweight, quick drying fabrics such as micro terry.  Containment can also be compromised a little.

These nappies have tended to become less popular since the introduction of pocket nappies, which have all the convenience but are much quicker to dry.  However, they can still be useful as part of a nappy system to be used when out and about or for when someone else is looking after your baby.