Swim diapers are no longer just a matter of preventing embarrassing accidents they have become an important public health issue. 27 states now require or encourage the use of approved swim diapers, waterproof with snug-fitting legs and waist, for diaper-aged children swimming in public pools, i play, and inc is the original swim diaper manufacturer with over 15 years of experience making, testing and improving our swim diaper. The i play. Patented ultimate swim diaper has three layers a waterproof layer to prevent leaks, an extra absorbent layer to absorb wetness and a wickaway lining to keep moisture from baby"s skin. We use materials that are naturally absorbent without superabsorbent gels or harsh chemicals to keep your baby clean and happy.