Baby Sleeper in TENCEL™ - Mini Mathletes

A baby who runs warm needs sleepwear that breathes all night, not just at bedtime.

Alligators on swings, elephants, kites, hopscotch — playground math.

Forbes named these the best baby pajamas in 2025. The sleeper is the workhorse of the under-layer — soft against the skin, quick to change in the dark, and built to survive the laundry a newborn puts it through.

Material. TENCEL™ Lyocell with a touch of spandex for stretch. TENCEL™ is the wood-pulp fiber Lenzing spins in a closed-loop process that recycles 99% of its water and solvents, certified to OEKO-TEX Standard 100.

The print. Cream ground with alligators on swings and seesaws, small elephants and pink bunnies, kites being flown by our Wolfie, hopscotch grids, balloons, small numbers, clouds, and trees.

Construction. Fold-over cuffs cover the hands for the first few months — no mittens to lose — then fold back when the baby wants them free. A two-way zipper runs chin to ankle and opens from the bottom for diaper changes, the neckline is tagless, and the shoulder and crotch seams are reinforced where a sleeper gets pulled on and off twice a day.

Sleepers and sleep bags work together. The sleeper is the layer underneath — it isn't meant to provide the warmth on its own. Pair with a 1.0 TOG TENCEL™ Sleep Bag for a 69–75°F nursery, a 0.5 TOG muslin sleep bag for 75–81°F, or wear alone in a warm room above 75°F if the baby protests the sleep bag.

Why TENCEL™ for a sleeper. A sleeper is worn most nights and washed two or three times a week, so we match the fiber to the job: TENCEL™ Lyocell keeps its softness and shape through heavy laundering. Our muslin pieces answer a different brief — swaddles, crib sheets, and 0.5 TOG bags use Tanboocel® Bamboo Viscose for breathability in the heat.

Sizing. 0–3M, 3–6M, 6–9M, 9–12M, 12–18M, 18–24M. Size to current measurement. A sleeper that's too long bunches at the hands and ankles and rides up overnight.

Care. Machine wash cold and tumble dry low. Don't bleach, and don't iron the printed areas. Wash it Tuesday, wash it Friday, wash it forever — TENCEL™ holds its surface through the routine.

Safety & certification. AAP safe-sleep compliant and tested to CPSC, CPSIA, and ASTM standards. The material is certified to OEKO-TEX Standard 100, and Loulou Lollipop is a Certified B Corporation.

Browse all TENCEL™ baby pajamas & TENCEL™ sleepers.

Free US shipping over $65. Free 30-day returns on unworn items in original packaging.

Part of the Big Dreams Sleep System. Sleepers and sleep bags in Mini Mathletes are built to layer together through the night — same print, one system. Complete the set with the Tanboocel® Bamboo Viscose 0.5 TOG Sleep Bag and TENCEL™ 1.0 TOG Sleep Bag.