beautiful baby in MORI’s Clever Year Round Sleep Sack

baby sleep sacks

Discover our collection of baby and toddler sleep sacks designed to help little ones sleep safely and comfortably through every season. From lightweight 0.5 TOG baby sleep sacks for warmer nights to cozy 2.5 TOG styles for winter, our award-winning collection is thoughtfully designed for every age and stage. Whether you need soft newborn sleep sacks for their first nights at home, or larger toddler sleep sacks as they grow, explore our clever safety features and signature organic cotton and bamboo from viscose fabrics to support better, safer sleep.

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Sleep Sack FAQs

Why do I need a baby sleep sack?

Sleep sacks provide a familiar sleeping environment for your little one, so they associate being placed inside one with going to bed especially helpful on holidays or visiting other people’s houses. Because there’s no need for blankets, they reduce the likelihood of your baby waking up cold because they’ve kicked off the covers.

Are sleep sacks safe for babies?

The Lullaby Trust, a charity which promotes safer sleep for babies, lists a sleep sack as an essential product in their guide. A baby sleep sack is a safe option as they prevent a little one’s head from being covered, plus they’re available in a variety of TOGs so you can choose the right one for the season.

What TOG should my baby’s sleep sack be?

The TOG determines the thickness of the sleep sack, the higher the rating, the warmer it is. Our sleep sacks are available in 3 TOGs; 2.5 for winter, 1.5 which is suitable for year-round use in a temperate climate and 0.5 TOG which has no padding for summer & holidays.

What should my baby wear underneath a sleep sack?

Babies can’t regular their temperature well, so dressing them appropriately is very important to keep them safe and comfortable. All our sleeping bags are made from breathable, thermoregulating and moisture-wicking organic fabrics to keep babies at the ideal temperature all night.

Learn how to dress your baby safely in summer.

How many sleep sacks does my baby need?

We recommend investing in 2 sleep sacks for your baby or toddler, this means you can have one on the go whilst the other is in the wash. You can buy a summer & winter TOG, or 2 of our year-round 1.5 versions. We also sell a Multi TOG option which has removable inner padding to transform it from a 2.5 TOG to a 0.5. Learn more about our Multi TOG sleeping sack.

What makes a MORI sleep sack a good choice?

As well as being made from the softest, safest fabrics, our sleep sacks are designed with plenty of features to make bedtime simpler. We’ve added zip fastenings for quicker changes, adjustable lengths to fit newborns up to 2 years and stroller openings so they snooze on the move.

Choosing the Right Sleep Sack TOG for Every Season
Finding the right baby sleep sack TOG can feel overwhelming for new parents, especially as room temperatures change throughout the year. Babies are less able to regulate their body temperature independently, which is why choosing the correct TOG rating can help keep little ones comfortable and prevent overheating during sleep.A lightweight 0.5 TOG style is designed for warmer rooms above 75°F. For milder temperatures, a 1.0 TOG sleep sack offers breathable comfort, alongside our 1.5 TOG sleep sack options. For colder winter nights, a 2.5 TOG design provides extra warmth when temperatures drop. For younger babies transitioning from swaddles, an appropriately......

Choosing the Right Sleep Sack TOG for Every Season

Finding the right baby sleep sack TOG can feel overwhelming for new parents, especially as room temperatures change throughout the year. Babies are less able to regulate their body temperature independently, which is why choosing the correct TOG rating can help keep little ones comfortable and prevent overheating during sleep.

A lightweight 0.5 TOG style is designed for warmer rooms above 75°F. For milder temperatures, a 1.0 TOG sleep sack offers breathable comfort, alongside our 1.5 TOG sleep sack options. For colder winter nights, a 2.5 TOG design provides extra warmth when temperatures drop.

For younger babies transitioning from swaddles, an appropriately rated sleep sack can help maintain a cozy, secure feeling while still allowing healthy movement during sleep.

Why Baby Sleep Sacks Are Recommended for Safer Sleep

Baby sleep sacks have become a trusted sleep essential for many families because they offer a wearable alternative to loose blankets in the crib. A baby wearable blanket or sleep sack helps little ones stay comfortably covered throughout the night without loose bedding around them.

Our collection includes thoughtful, safety-first details designed to help parents feel more confident at bedtime. Features such as fitted neck openings, secure fastenings and adjustable armholes help little ones stay safely positioned through the night, while a zip up sleep sack allows for easier overnight diaper changes with less disruption to sleep. Carefully placed zipper guards also help protect your little one’s delicate skin.

For wriggly sleepers who tend to kick off blankets, a baby sleep sack can also help maintain a more consistent level of warmth overnight, reducing wake-ups caused by feeling too hot or too cold.

Breathable Fabrics to Help Babies Sleep More Comfortably

Heavy fabrics and too many layers can quickly lead to overheating, particularly during warmer nights or when babies are unwell. Our newborn sleep sacks, infant sleep sacks and selected cotton sleep sack styles are crafted from MORI’s signature blend of sustainably sourced bamboo from viscose and organic cotton, chosen for its breathable, moisture-wicking and temperature-regulating properties. Our bamboo sleep sacks help air circulate more easily around delicate skin while remaining exceptionally soft for little ones.

Pair a lightweight summer sleep sack with breathable rompers or footie pajamas for warmer nights.

H2: Baby & Toddler Sleep Sacks That Grow With Your Child

For newborns and younger babies, our 0-6M baby sleep sack is designed with plenty of room for natural movement and healthy hip development, creating a comfortable fit from those first newborn nights through the early months. With an adjustable length designed to grow with your baby, there’s no need to size up every few months.

As babies become more active, our 6-24M sleep sack takes them from infancy right through to the toddler stage. The adjustable design can be shortened for smaller babies and lengthened as they grow, giving wriggly sleepers plenty of space while helping you get years of use from fewer sleep sacks.

To help you find the perfect fit, our sizing grows with them:

0 to 6 Months: Our newborn and baby sleep sack is designed for those earliest months, with an adjustable length for a comfortable fit as your baby grows.
6 to 24 Months: One infant sleep sack takes them from 6 months right through to their second birthday, adjusting in length along the way.
2 to 4 Years: Our larger toddler sleep sack is designed to last from 2 to 4 years, offering familiar bedtime comfort with plenty of room for growing little ones.