Car Seat Safety: 5-Point Harness vs 3-Point Harness

UK Law states that a car seat must be used until a child reaches the age of 12 or a height of 135cm, whichever comes first. That’s a huge amount of time to be using something of such importance on a regular basis, so a quality car seat with an effective harness is a crucial investment for parents.

There’s so much to think about when purchasing, and with many of us spending a significant amount of time on the road, ensuring that your child is comfortable and secure is an absolute must. It’s therefore understandable that you’ll want to weigh the pros and cons of your options before making a decision.

The purpose of a harness is to keep your child safe and secure and protect them in the event of a collision. It can be attached to the car seat in a number of ways depending on the type of harness, and it’s best to choose a car seat based on your child’s height and weight.

The seemingly never-ending options and wealth of information online can sometimes be overwhelming and make the purchasing decision even more difficult.

We’ve taken the liberty of assessing the effectiveness of the 5-point and 3-point harness, and which one we think you’d be best investing in.

Here’s our evaluation of the two to help you with your choice and give you the best peace of mind. 


3-Point Harness

The 3-point harness has straps over the shoulders and between the legs. It acts as more of a safety belt than a traditional harness that is modelled after the racing-car style, so tends to be used more frequently for older children aged 4 to 12, rather than infants and toddlers. 


Despite not being as secure of an option, it does have certain positive elements. As it is fastened around the back of the car seat rather than over the front of it, the belt retracts on its own, minimising the possibility of becoming loose.

This also means that you don’t have to worry about the complex process of installing it to be a perfect size, as it adjusts itself to align with your child’s natural movements.

The 3 point harness allows for freer movement of the neck and spine, meaning it may be more comfortable in this area, and it is also more generous with weight limits, making it a good option for older kids.


As expected, there are a fair number of cons that may arise with the 3 point harness.

Firstly, it is much easier to wriggle out of than the more secure alternative, so lively children who move around a lot may be able to force the shoulder strap out of its intended position.

It can also be incredibly easy for the child to move out of the ideal sitting position when sleeping, which can put unnecessary strain on their body.

With fewer points of restraint on the body, it also makes it more likely that a child will be injured in the event of a crash, with ejection being a possibility, especially for those who have managed to squirm their way out of the optimal position.

5 Point Harness

As mentioned, a 5-point harness is designed after a racing-car style harness, so it of course provides significant support and has an extra two attachment points to restrain your child at the shoulders and hips.

The great news about this style is that it makes the risk of ejection extremely unlikely in the event of a severe crash or collision, provided it is installed in the correct way.

Because the child is held tightly against the seat, any crash that occurs will distribute the impact more evenly across the body, and it of course means that the child remains in the optimal sitting position at all times, whether they are asleep or not.

On the flip side, there are certain elements to be aware of when considering purchasing this type of harness.

Without proper installation, it won’t be nearly as effective, so the harness straps must be tightened and “pinch tested” to ensure that there is less than one inch of movement between the harness and child.

Just as important is checking that it hasn’t been fastened too tightly, as this will put pressure on the body and make for an uncomfortable and unpleasant experience for your child.

It may be worth seeking assistance from a professional or the harness provider to be absolutely sure that it is installed correctly, otherwise, the chance of injury will be greatly increased.

These types of harness also have a weight limit (generally 18kg) so are not suitable for older children and can only be used until the child grows out of it.

Which is best for your child?

After weighing the pros and cons of each option, it’s pretty clear that the best option of the two, especially for younger kids, is the 5-point harness.

With the extra two-point security keeping the child securely in place at all times, it provides extra peace of mind and minimises worry about the possibility of the harness position being altered.

Young children are fragile- and just like racing drivers need premium protection due to the dangerous nature of their sport- babies and toddlers require the same level of support to keep them safe in the car.

That being said, the 3-point harness is a good option for children over the age of 4 who exceed the weight limit of the 5-point device.

The range of movement it allows in the neck and spine is also a huge positive and provides extra comfort in this area for long journeys.

Ultimately, the 3-point harness will keep your child in place and provide adequate support, but for very young children the extra layer of support offered by the 5-point harness cannot be beaten and should definitely be considered as an investment for your child’s safety.

The best option is to use this until your child outgrows it, at which point you can move to a booster seat with a 3-point harness.

Want more info on car seats? 

Don’t miss our buying guides for best 360 car seat in the UK, best Graco car seats and best Maxi Cosi car seats.

Kate the toddler review

The author: Jose Martinez

Hi there! My name is Jose, and I’m a proud dad to a beautiful 4 year old. As a parent, I know firsthand how overwhelming it can be to navigate the world of parenting and child-rearing. There are so many choices to make, from the foods we feed our little ones to the toys we buy them to the clothes they wear. But one thing that’s always been important to me is finding the best products available for my child.

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