Swaddles and sleep sacks are two essential tools in a parent’s arsenal when it comes to encouraging better sleep for babies. Both are cozy wraps that provide comfort, security, and warmth, which can mimic the snug feeling of being in the womb. It’s important to know that they’re not interchangeable, however. Understanding the benefits of each and using them safely and according to developmental milestones can help your little one develop healthy sleep habits.

What is the difference between a sleep sack and a swaddle?

What is swaddling?

Swaddling involves wrapping a baby in a snug blanket with their arms and legs close to their body. It reduces the startle reflex and promotes better sleep, allowing babies to fall asleep faster and stay asleep for longer stretches of time.

How to wrap a swaddle

How to Swaddle an Infant

Lay the blanket down on a flat surface with one corner folded down. Place baby on their back with their head above the folded corner. Wrap one side of the blanket snugly across their chest and tuck it under their opposite arm. Repeat this with the other side, making sure that the blanket is snug and secure but not so tight that it’s affecting their ability to breathe.

What are some swaddle alternatives?

Swaddling with a blanket isn’t always easy, especially if your little one is particularly wiggly. Some products offer the benefits of a swaddle without the tedious wrapping—look for so-called peanut-shaped sleep sacks. HALO’s options, in particular, are recommended by many hospitals because they’re cost-effective and have reliable thermal ratings, which means baby will be kept comfortably warm. When looking for a swaddle, know that the American Academy of Pediatrics advises against weighted swaddles and considers them dangerous for newborns.

When is it time to transition to a sleep sack?

When baby begins attempting to roll over, it’s time to stop swaddling and start using a sleep sack. Each child is different—this can happen as early as two months or as late as four months (or more)! If your little one consistently escapes their swaddle or seems restless when swaddled, you may also want to switch to a sleep sack.

What is a sleep sack?

Think of a sleep sack as a wearable sleeping bag—it’s a sleeveless garment that zips or snaps around the body, covering babies from their shoulders to their feet while still allowing their arms to move freely without the risk of a loose blanket. Additionally, sleep sacks allow baby to roll freely without constraint, and promote healthier hips because of room to kick. At one year of age, it is safe to transition from sleep sack to blanket. However, many parents find sleep sacks, or sleep sacks with foot holes to be helpful into toddlerhood.

How to choose a sleep sack

If you don’t know where to start your search, the Harbor Care Team suggests HALO’s sleep sacks. Avoid sleep sacks that are weighted or constrict baby’s hips, as they can hinder baby’s movement and may be dangerous.

Make a note of the thermal overall grade (TOG) rating of the sleep sack, which indicates how warm a garment is. The TOG rating of the sleep sack you choose should be informed by your regional climate and home’s ambient temperature (remember, 68–72 degrees Fahrenheit is ideal!). Look for natural fabrics like cotton, wool, and bamboo, which are soft, breathable, and can be hypoallergenic.

How to transition from a swaddle to a sleep sack

Switching from a swaddle to a sleep sack is an environmental change for your little one and may contribute to more frequent wakings or difficulty falling asleep for a period of time. Know that this is temporary—baby just needs to get used to their new clothing! 

It’s still important to adhere to your sleep schedule and provide a dark, quiet, and safe environment. If you don’t have a sleep schedule, you can reference our Sleep Guide as a starting point or talk with a Harbor Sleep & Wellness Coach. Even in a sleep sack, baby should be put to sleep on their back on a firm mattress without any loose bedding.

To recap

The switch from swaddle to sleep sack is typically informed by baby’s developmental progress, but you may decide to switch to a sleep sack if they’re a skilled escape artist or seem fussy when swaddled.

After switching to a sleep sack, they may experience a small sleep regression. Know that they just need to get used to the new sensation, and trust in the sleep training progress you’ve already made to date. Read more about sleep regressions and solutions here.

Swaddles and sleep sacks help your little one to get better sleep, which also means they help you get the sleep you need to be the best possible parent. If you have any questions along the way, reach out to Harbor. Our infant care experts are available to answer any questions you might have about swaddling challenges or sleep sack recommendations.