i-Size Car Seats

i-Size is associated with the newer UN R129 car seat safety regulation. R129 car seats are classified primarily according to a child's height rather than the older weight-based Group system and include side-impact testing as part of the approval process.

The terms are often used together when describing modern car seats. R129 is the safety regulation, while i-Size was introduced within R129 to improve compatibility between approved child restraints and vehicle seating positions. Always check the individual car seat's R129 approval and usage range.

No. Not every R129-approved car seat requires ISOFIX. Depending on the seat and approval, installation may use ISOFIX, the vehicle seat belt or a combination of approved methods. Always follow the installation instructions for the individual car seat.

R129 car seats are primarily classified by the child's height, such as 40–87cm, 61–105cm or 100–150cm. Choose a seat that covers your child's current height and follow any additional age or weight limits specified by the manufacturer.

Under R129, children must travel rear-facing until at least 15 months old. Many seats allow rear-facing travel considerably longer, which can provide additional protection for a young child's head, neck and spine. Always follow the approved limits of your chosen seat.