In Ireland, a child under 150cm in height or 36kg in weight must use a child restraint suitable for their size while travelling in a car or goods vehicle. The driver is responsible for ensuring passengers under 17 are properly restrained. A rear-facing child seat must not be placed in a front passenger seat with an active frontal airbag.
The legal threshold is not the same as the best time to move a child into an adult belt. The RSA recommends keeping a child in a suitable restraint until 150cm tall, and says children must remain rear-facing until at least 15 months. A seat’s own height or weight limits still matter: outgrowing the manufacturer’s range means it is time to choose the next appropriate restraint, not to use a seat beyond its label.
New child seats sold in the EU since 1 September 2024 must meet R129 (i-Size). A seat bought earlier under the older R44 standard can still be used if it is in good condition and suitable for the child. The important distinction is between the rules for newly sold seats and the continued use of a compliant older seat.
Fit is a separate issue from choosing the right model. In 2024 the RSA’s Check it Fits service checked more than 5,800 seats; 54% needed some adjustment, and 20% required major corrections. The free nationwide service checks installation and demonstrates how to fit the seat. Before buying, test the restraint in your own car, especially if fitting three seats across the rear bench. A model that fits another car may not fit yours safely.
