Rear facing law
Rear facing child car seat law
A height based R129 seat must face the rear until the child is over 15 months old. A rear facing baby seat must never be placed in front of an active frontal airbag.
These rules apply in Great Britain.
Rules and figures checked on 10 September 2026.
Over 15 months means after the threshold
At 15 months the R129 seat must still face the rear. Once the child is over 15 months, Great Britain law permits a forward facing child car seat, subject to the height and weight limits on its approval label.
The front airbag must be inactive
GOV.UK requires any front airbag to be deactivated before a rear facing baby seat is fitted in the front passenger seat. The seat must also be suitable for the child and installed according to the manufacturer instructions.
Common questions
- Can an R129 seat face forward at exactly 15 months?
- No. The published rule says rear facing until the child is over 15 months old, so exactly 15 months remains inside the rear facing period.
- Can a rear facing baby seat go in the front?
- It can only be fitted there if the frontal airbag is deactivated and the seat and vehicle manufacturer instructions permit the installation.
- When can a child use an adult seat belt?
- A child can use an adult seat belt from their 12th birthday or once they reach 135 cm tall, whichever happens first. The belt must be worn where one is fitted.
Related pages
- Child car seat law and seat checkerIn Great Britain, a child normally needs an approved child car seat until their 12th birthday or until they reach 135 cm, whichever happens first. The seat must match the child's height or weight and be fitted as its manufacturer directs.
- i-Size and R129 child car seatsGOV.UK identifies legal height based restraints by a capital E in a circle and R129 on the approval label. These seats are commonly called i-Size seats. They must remain rear facing until the child is over 15 months old.
- Booster seat law by height and weightUnder ECE R44, group 2 covers 15 kg to 25 kg and group 3 covers 22 kg to 36 kg. Approved R129 boosters instead use the height range and any maximum weight printed on their label.
- Backless booster seat lawFrom 9 February 2017, manufacturers could introduce new backless booster models only for children at least 125 cm tall and at least 22 kg. Existing approved group 2 cushions were not withdrawn by that change.
Sources
Each legal threshold and exception above comes from the linked government guidance.