The Sleep Onesie is a TOG-rated sleep sack alternative, designed to be worn on its own during sleep or with a Romper/PJs underneath for warmth and comfort.
Size Guide
Sleep Onesie
Please use your child's height to find the most appropriate and safe size for them. The Sleep Onesie should be fitted around the neck to avoid your child slipping through. 2.5 TOG and 3.5 TOG Sleep Onesies should not be used in a 5-point harness or car seat for safety reasons.
| ergoPouch size | 6-12M | 12-24M | 2-3Y | 4-5Y | 6-8Y | 8-10Y | 10-12Y |
|---|---|---|---|---|---|---|---|
| Same as size | 0-1y | 1-2y | 2-3y | 4-5y | 6-8y | 8-10y | 10-12y |
| Pouch length (cm/inch) | 74cm / 29.1" | 84cm / 33.1" | 88cm / 34.6" | 98cm / 38.6" | 110cm / 43.3" | 120cm / 47.2" | 130cm / 51.2" |
| Chest width (cm/inch) | 27.5cm / 10.8" | 30.5cm / 12" | 32cm / 12.6" | 35cm / 13.8" | 38cm / 15" | 40cm / 15.7" | 42cm / 16.5" |
| Child height (cm/inch) | 68-84cm / 26.8 - 33.1" | 76-92cm / 29.9 - 36.2" | 92-100cm / 36.2 - 39.4" | 108-115cm / 42.5 - 45.3" | 120-130cm / 47.2 - 51.2" | 130-140cm / 51.2 - 55.1" | 140-150cm / 55.1 - 59.1" |
- Free delivery on orders over $70*
- Estimated dispatch: 10 January 2026
- Extended Holiday Returns until Jan 31st
- Tom W.Verified Buyer12/31/25ReviewingSleep Onesie 3.5 TOG SageRated 5 out of 5 starsOur Favorite Sleepsack
Fantastic quality. I couldn't find a sleepsack that would fit my 4 year old for the winter months until I came across ergoPouch. I love that it is machine washable and tumble dryable as well. I love that it also has foot covers that go over the feet. I just wish the price was lower.
- Jennifer W.Verified Buyer12/23/25ReviewingSleep Onesie 2.5 TOG Oatmeal MarleRated 5 out of 5 starsLove ergopouch
We love this. It’s so soft. We are on to our 10th pouch! We bought them from when they were newborns until 5. They’re perfect for a good nights sleep.
- Robertas D.Verified Buyer12/17/25ReviewingSleep Onesie 2.5 TOG DaisiesRated 4 out of 5 starsGood
It is a good sleeper set, however it is not easy to change napkins when your baby’s sleeps. Other then that all good
