When should you stop using a sleep sack?

Short answer? Later than most people think.

Something people have been asking me lately is "when should they stop using a sleep sack.?" The answer often surprises people.

If your child is happy in a sleep sack, my honest advice is to keep it for as long as you can or at least until they grow out of the largest size.

Sleep sacks are one of those quietly brilliant sleep associations that often get ditched too early, even though they’re doing a lot of good overnight.

Why sleep sacks work so well for babies and toddlers

Sleep sacks help keep children warm all night and that matters more than we often realise.

Most toddlers don’t reliably stay under blankets until they’re much older. They wriggle, roll, kick everything off… and then wake up cold at 3am half way across the bed because they are cold.

Cold children tend to wake more frequently. And honestly? If we can easily reduce environmental causes of night wakes, I’m on board. Warm kids sleep better.

So when should you stop using a sleep sack?

There are really only a few good reasons to stop:

1. They’ve outgrown the largest size

Many sleep sacks go up to around 4 years old. If they physically no longer fit safely, that’s your cue.

2. They’re climbing out of the cot

This one’s about safety. If your child is attempting to climb out, it’s time to transition to a bed and that usually means moving away from a sleep sack too.

3. They’re removing it constantly anyway

Some kids decide they’re done, no matter how brilliant the sleep sack is. If it’s becoming a nightly battle, we want to work with your child, not against them.

If your child keeps taking their sleep sack off

Before you give up entirely, try a few simple tricks:

• Put the sleep sack on backwards

• Put it on inside out (zips are less tempting this way, but also tricky for you)

• Put a t-shirt over the top of the sleep sack

What if they stop using a sleep sack but hate blankets?

If your child ditches the sleep sack early and isn’t ready for blankets yet, focus on layers instead. Adding extra warmth through pyjamas (rather than relying on a blanket they’ll kick off) can make a big difference to overnight comfort and sleep quality.

The bottom line:

Sleep sacks aren’t something you need to rush away from.

If they’re working, they’re safe, and your child is comfortable then there’s no prize for stopping early. Support warmth, reduce unnecessary wake-ups, and choose what works best for your child and season of life.

And if in doubt?Warm kids sleep better 🤍

Aleisha Wilkinson