What should my child wear in a car seat?
- Mar 25
- 2 min read
When it comes to car seat safety, clothing matters more than many people realise. Both in winter and summer.
It’s not about style or layers for warmth - it’s about whether the harness can do its job properly in a crash.
The simple rule?
Indoor clothing only.
Why clothing affects car seat safety
Car seat harnesses are designed to hold a child securely by sitting flat and snug against the body.
Thick or bulky clothing, like coats or snowsuits, creates a hidden gap between the harness and your child.
In everyday use, the harness may feel tight. But in a crash:
The padding compresses
The harness slackens
The child can move further than intended, or even be ejected
This reduces how effectively the harness can protect them.
What is safe for a child to wear?
A good way to think about it is “indoor clothing”.
Safe options include:
Thin, well-fitting tops and layers
Leggings, joggers, or tights
Lightweight jumpers or cardigans
Clothing without bulky hoods
It’s also important to:
Ensure nothing is bunched up behind the back or at the hips
Keep a layer between the harness and skin for comfort
Check the harness is snug using the pinch test
What should be avoided?
Some items can interfere with both harness fit and overall safety.
These include:
Thick coats and jackets
Snowsuits and puddlesuits
Fleece onesies or “teddy bear” style outfits
Footmuffs or car seat wrap blankets that go behind the child
Headwear like hats, turbans, or large headbands
These items can:
Prevent the harness from tightening properly
Introduce slack in a crash
Increase the risk of overheating
But what about keeping them warm?
No one wants a cold child - especially on a frosty school run.
The safest approach is:
Dress your child in thin layers
Secure them in the harness first
Then add warmth over the top
You can use:
Blankets tucked over the harness
Coats worn backwards (arms in, front over the harness)
Car-safe layers that don’t go behind the child
The car seat itself also acts as a layer, so children often don’t need as much as we think.
Why overheating matters too
Overheating isn’t just uncomfortable - it’s also a known risk factor for Sudden Infant Death Syndrome (SIDS) in babies.
Bulky clothing, combined with a warm car environment, can increase this risk.
Keeping clothing light and breathable helps manage temperature more safely.
FAQs
Can my child wear a coat if I loosen the harness?
No - loosening the harness to accommodate a coat creates slack, which reduces protection in a crash.
Are car seat blankets safe?
Only if they go over the harness, not underneath or behind the child.
How can I tell if the harness is tight enough?
Use the pinch test - if you can pinch the harness at the shoulder, it’s too loose.
