The Good Egg Car Safety Blog

What are group 123 car seats

A group 123 car seat is a combination seat that is approved for children weighing 9kg, and it will last them right through, until they no longer need a child seat. They are often an economical solution, as they last a long time.

Group 123 car seats are generally forward facing, although there are some which now allow your child to be rear facing to 13kg or 18kg. Your little one is safest rear facing for as long as possible.

There are different options to consider when choosing a group 123:

  • ISOFIX or seat belt fitment
  • Harness or Impact Shield
  • Recline

ISOFIX or Seat Belt Fitment

It is more common for group 123 car seats to be fitted with the adult seat belt, however there are some ISOFIX + Top Tether group 123 car seats available. Both methods of fitment are safe, however ISOFIX is considered safer as it reduces the risk of incorrect fitment.

Harness or Impact Shield 

Child seats are most commonly seen with a 5 point harness to restrain a child, and lots of group 123 seats use a 5 point harness. There are also impact shield seats available, which use a protection cushion placed in front of the child and secured with the seat belt, instead of a harness.


Not all group 123 seats have a recline option, and some of those that do have varying levels of recline. Take this into account when choosing a group 123 car seat – if your little one is a sleeper in the car, you may prefer a seat with a recline.

Weight limits

Most group 123 car seats allow the harness to be used until the child weighs 18kg, and then the seat converts to a group 2,3 high back booster for use right the way through until your child no longer needs a car seat.

For children who are higher on the percentile chart, and are likely to reach 18kg long before they are age 4, it is worth considering a seat with a 25kg harness limit, to ensure you get maximum harness use.

The only group 123 car seat currently on the market with a 25kg harness limit is the Britax Advansafix

What is a top tether?
The hidden projectile in your car - Booster seats


No comments made yet. Be the first to submit a comment
Already Registered? Login Here
Tuesday, 07 December 2021

By accepting you will be accessing a service provided by a third-party external to

Britax iSize VisualGet your FREE guide on all you need to know about i-Size!

Enter your details and you will receive our free guide on all you need to know about i-Size.

Supported By

Arnold Clark
Britax logo

Endorsed By

RSS logo
Police Scotland Logo
Scottish Fire
IAM RoadSmart_Logo_RGB_72dpi
Baby Products Association