Kid's One-Piece Swimsuit (Swimwear)

Fabric runs unbroken from the shoulders down to the leg openings, with no split at the waist, and that continuity is the whole design. Nothing rides up separately, slides down separately or comes off separately. Size runs usually open around 6 months and carry through the big kid range, and most carry a front lining, a pale second layer that keeps the knit opaque once it is soaked and clinging.

Backs are where these suits differ, and where one either stays on or does not. Straps crossing at the shoulder blades, or a racerback joining them into a single strip, cannot slip off an arm as a child hauls up a pool ladder or takes a wave. Straight straps set wide apart look tidier on the hanger and slide off narrow shoulders all summer long. Leg openings deserve the same look: covered elastic, sewn inside a folded edge, holds its snap far longer than elastic stitched flat onto the surface, and a slack leg is the first place a suit begins to gape.

Compared with a Two-Piece Swim Set, this trades bathroom independence for security. This is a fair swap for a toddler and a poor one for a seven year old. A Sun Suit pushes the same joined idea further by adding sleeves, full legs and a zipper, so it guards more skin and takes much longer to peel off wet. A Rash Guard is no alternative at all, since it layers over a one-piece. The pair together is the standard combination for a long day outdoors.

Swim lessons, water slides and open water all reward the joined cut, because each applies a sudden pull that a two-piece answers by separating. Children still carried in and out of the water suit it as well, since an adult's grip lands on fabric rather than slippery skin. Bathroom trips are the cost. The whole suit comes down to the ankles on a wet floor, and a newly toilet trained child resents that several times an afternoon. Check the fit by hooking a finger under each strap and lifting. More than roughly an inch and a half of give means the torso length is too long. Water weight will only pull it lower.