There is no hard and fast rule, but many pediatric providers encourage you to wait until six months of age. By then, your baby will have much better head control, won’t be as vulnerable to germs and illness, and will also be able to wear sunscreen. Always hold your baby in water, and do not rely on personal flotation devices. If your baby is prone to eczema, dermatologists recommend applying petroleum jelly to their skin beforehand and rinsing off with warm water after.