How to check car rental child seat rules

What are the UK rules on child car seats?

The age and height test comes first. Children must normally use a child car seat until they are 12 years old or 135 centimetres tall, whichever comes first, while children over 12 or more than 135 centimetres tall must wear a seat belt. [1]

Height-based seats. A height-based seat must be rear facing until the child is over 15 months old, and a forward-facing child car seat can be used once the child is over 15 months. [1] The seat has to be checked to make sure it is suitable for the height of the child. [1] Only approved height-based child car seats can be used in the UK, and these carry a label showing a capital "E" in a circle and "R129". [1]

Weight-based seats. With the weight-based system, the seat a child can use, and the way the child must be restrained in it, depends on the child's weight. [1] Only approved weight-based child car seats can be used in the UK, and these carry a label showing a capital "E" in a circle and "ECE R44". [1] There may be more than one type of seat within the group that matches a child's weight. [1]

How do you check a child seat before you drive away?

Fitting rules decide whether a particular seat can be used in a particular car. A child car seat can only be used if the car's seat belt has a diagonal strap, unless the seat is specifically designed for use with a lap seat belt or is fitted using ISOFIX anchor points. [1] A child car seat must not be fitted in a side-facing seat, and any front airbags must be deactivated before a rear-facing baby seat is fitted in a front seat. [1]

Two checks come before the car moves. First, the seat must be suitable for the height of the child under the height-based system, or match the child's weight under the weight-based system. [1] Second, the seat must carry the approval label for the system it belongs to, because only approved child car seats can be used in the UK. [1]

Suitability is set by the child, not by the seat being available. Because the correct seat depends on height or weight, the seat that fits one child is not automatically the right one for another, so the label and the stated height or weight range have to be checked against the child in front of you. [1]

Exceptions and limits

• Disability or medical condition. The same rules apply for children with disabilities or medical conditions, but they can use a disabled person's seat belt or a child restraint designed for their needs, and a doctor can issue an exemption certificate if a child is unable to use a restraint or seat belt because of their condition. [1]
• Booster cushions. Manufacturers can now only make booster cushions approved as group 3, but this does not affect existing booster cushions in group 2, which can still be used. [1]
• Older and taller children. The child seat requirement ends at 12 years old or 135 centimetres, whichever comes first, and a seat belt is then required. [1]
• Country of rental. The requirements described here are the United Kingdom rules; other countries set their own child seat requirements, and a rental company's own supply conditions sit on top of whatever local law applies. [1]

Frequently asked questions

At what age can a child stop using a car seat in the UK?

A child must normally use a child car seat until they are 12 years old or 135 centimetres tall, whichever comes first. [1] After that, the child must wear a seat belt. [1]

Can a rear-facing baby seat go in the front passenger seat?

It can, but any front airbags must be deactivated before the seat is fitted, and a child car seat must never be fitted in a side-facing seat. [1]

How do you know a child seat is approved for use in the UK?

An approved height-based seat shows a capital "E" in a circle and "R129", while an approved weight-based seat shows a capital "E" in a circle and "ECE R44". [1] Only approved seats can be used. [1]

What happens if a child cannot use a standard seat?

The same rules apply for children with disabilities or medical conditions, but a disabled person's seat belt or a restraint designed for their needs can be used, and a doctor can issue an exemption certificate where the child is unable to use a restraint or seat belt because of their condition. [1]

Related pages

Start with the car rental guide, then see optional extras and fees for how add-ons are handled at the counter, and the pickup and return checklist for what to inspect before leaving the lot. Definitions of common travel terms sit in the glossary.

Sources

Sources accessed on 18 October 2026. Child seat laws outside the United Kingdom and the individual child seat supply policies of rental companies are not covered here.

1. GOV.UK, Child car seats: the law, checked 18 October 2026