Baby bodysuits are the most practical base garment for newborns and infants from NB through 18M. They function as a standalone top in warm weather and as a tucked-in base layer under sleepsuits, trousers, and dungarees. The three-snap crotch closure keeps the bodysuit from riding up during movement and makes nappy changes faster than a top that requires full undressing. All bodysuits in this range are 100% combed ringspun cotton and pre-shrunk to hold size from the first wash.
Baby Bodysuits Short Sleeve and Long Sleeve: When to Choose Each
Short sleeve bodysuits are the year-round workhorse. In summer they work as a standalone piece. In winter they layer under a long sleeve top or sleepsuit without the extra sleeve fabric bunching at the forearm. Long sleeve bodysuits provide more warmth as a standalone piece in cool rooms or on mild autumn days and reduce the number of layers needed at night when a sleepsuit adds too much warmth. Most parents keep both styles: 3 to 4 short sleeve and 2 to 3 long sleeve covers most seasonal conditions across the first six months.
Sizing Baby Bodysuits: NB to 18M
Baby bodysuit sizes follow weight bands more reliably than age: NB (newborn, up to approximately 10 lbs / 4.5 kg), 0-3M (up to 13 lbs / 6 kg), 3-6M (up to 17 lbs / 7.5 kg), 6-9M (up to 20 lbs / 9 kg), 9-12M (up to 22 lbs / 10 kg), 12-18M (up to 26 lbs / 12 kg). If your baby is between weight bands, choose the larger size. A bodysuit that is slightly too big is easier to work with than one that is too small: the snap closure can accommodate a few extra centimetres of torso length, but a too-short bodysuit will not snap comfortably. Most families find that NB is outgrown faster than expected for full-term babies.
Baby Bodysuit Fabric: 100% Combed Cotton and Snap Closure
Combed ringspun cotton is the standard for infant clothing in direct contact with skin. The combing process removes short, rough fibres before spinning, producing a smoother, softer yarn than uncarded cotton. The result is a fabric that does not become scratchy after repeated washing. The envelope neckline widens during dressing to pass over the baby's head without forcing the neck forward. The three-snap crotch closure uses flat metal snaps that do not protrude on the inside of the garment. Machine wash cold on a gentle cycle, tumble dry low or air dry.
For older infant and toddler styles in the same cotton construction, see baby clothing. For the next size up after 18M in lightweight cotton tops, see toddler t-shirts.