Frequently asked questions

• Drivers have a legal responsibility to ensure that all passengers under 17 are appropriately restrained in the vehicle.
• All children under 150cm in height or 36kg in weight must use a child restraint system (CRS) suitable for their height and weight while travelling in a car or goods vehicle (except taxis). 
• It is illegal to place a rear-facing child car seat in the front passenger seat where there is an active airbag.
• Children must travel in a rear-facing car seat until they are at least 15 months old.  Safety experts recommend keeping children rear-facing for as long as possible.

A child can legally stop using a child car seat once they reach 150cm in height or 36kg in weight. 

Safety recommendation: Children should continue using a car seat until they reach 150cm, regardless of weight.

There is no law against children sitting in the front seat as long as they are using a child restraint suitable for their height and weight. However:

• It is illegal and highly dangerous to place a rear-facing child car seat in the front passenger seat where there is an active airbag. 
• The back seat is the safest place away from airbags and the dashboard.
• If a child must travel in the front passenger seat, ensure they are using a forward-facing car seat that is suitable for their height and weight.  Where possible, the biggest and strongest child should occupy the front seat.  Position the front passenger seat as far back from the dashboard as possible, as this could help reduce the severity of injuries should the airbag deploy in a collision.

 

Children must remain rear-facing until they are at least 15 months old. We recommend keeping children rear-facing for as long as possible (often up to age 4 or beyond ). 

Only switch when the child outgrows the rear-facing limits (height or weight), not just because they reach a certain age.

The transition from a child car seat to a booster seat should be based on your child’s height rather than their age.

• High-back booster seat:  recommended for children between 100cm and 150cm
• Backless booster seat:  recommended for children between 125cm and 150cm

 Booster seats help position the vehicle seat belt correctly across a child’s body, reducing the risk of serious abdominal and neck injuries in a collision.  The seat belt should rest across the shoulder (not the neck) and across the pelvis (not the stomach).

 High-back booster seats provide additional head and side-impact protection and should be used for as long as possible, up to a height of 150cm.  Backless booster seats do not provide head or back support and are intended for older, taller children who are nearing the end of their time using child restraints.  

Once you have followed the instructions on how to fit the child car seat, check the fit by:

1. Movement test: Hold the seat at the base and try to move it side-to-side and forward.  It should not move more than about 2-3cm (1 inch).  If it wobbles more than that, it’s too loose.
2. Installation check:

• For ISOFIX, make sure both connectors are fully clicked in (listen for an audible click and look for the green indicator).
• For seatbelt installation, ensure the belt is routed exactly as shown in the manual and pulled tight with no extra slack. 

1. Visit our ‘Check it Fits’ service to get your car seat checked by one of our experts.  This service is a full-time, nationwide, free service and our experts will check the car seat is fitted correctly, and will answer any questions you might have.  Check the upcoming ‘Check it Fits’ locations here.

Buying new is always the safest option.  Second-hand car seats can be safe, only if the following applies:

• You know and are completely sure of its history
• Must never have been involved in a crash (even if no damage is visible)
• It is within its expiry date (generally 5-10 years; check the exact expiry date which can be found on the sticker on the seat or embossed in the plastic shell)
• Must include all its original parts and instructions
• It comes from a trusted source (e.g. family or close friend)
• It complies with EU safety standards – check for the orange ‘E’mark label.  The label should indicate compliance with either ECE R44/04 (older standard) or R129 (i-Size), which is the new standard.

 

There is no one-size-fits-all answer to fitting three child car seats across the back seat, as it depends on the make and model of your vehicle, the child car seats you are using, and the needs of each child.  Before purchasing child car seats, it is important to physically test the car seats in your vehicle to ensure they fit correctly and can be installed safely. 

Our Check it Fits experts have extensive experience and knowledge of fitting different combinations of child car seats in a wide range of vehicles and are happy to provide advice and guidance.

If you need help, simply complete our Ask a Question or Request a Call Back form and one of our child car seat experts will get back to you.

• Yes, a car seat should be replaced after a collision, even if there is no visible damage. Impact forces can cause hidden structural weaknesses that may reduce the seat’s ability to protect a child in another collision.  As a general guideline, if the vehicle sustained more than bumper damage, you should seek advice and consider replacing the car seat.  We recommend contacting the car seat manufacturer directly for guidance specific to the make and model of your child car seat. 
• If the car seat is being replaced following a collision, it should be made unusable before disposal.  For example, cut the harness straps and/or damage the polystyrene components to help ensure the seat cannot be use again. 

 

ISOFIX

• A built-in system that lets you attach a child car seat directly to your car’s chassis
• Uses metal anchor points instead of a seat belt
• Reduces the risk of incorrect installation
• Often includes visual indicators to confirm it’s fitted properly

 i-Size

• A European safety standard for car seats (Also known as R129)
• Requires rear-facing car seats for longer (at least until 15 months)
• Classifies seats by child’s height rather than weight
• Includes improved side-impact protection testing
• Designed to work with ISOFIX systems for better compatibility
• Since September, 2024, only child car seats approved under R129 (iSize) standard  can be sold within the EU.  However, child car seats certified under the older R44 standard that are already in use remain legal and can continue to be used.

 ISOFIX is how the seat attaches to the car, while I-Size is the safety standard the seat is built to meet.

It is very important to make sure that the child car seat is suitable for your child’s weight and height. Refer to the manufacturer’s guidelines on each child car seat. 

 

When choosing a new child car seat, make sure that it fits in your car (or cars, if you use it in more than one) and is suitable for the height and weight of your child. For information on the appropriate child car seat by height and weight, click here .

If your child exceeds either the height limit or the weight limit for their current seat, you should stop using that seat as they have outgrown the seat and should transition to the next suitable seat. 

Always follow the manufacturer’s limits.  For information on the appropriate child car seat by height and weight, click here. 

The shape and design of car seats, the length of seatbelts, the location of seatbelt anchor points, and the position and height of ISOFIX fittings vary from one vehicle to another. As a result, not all child car seats are compatible with all cars. For example, a seatbelt in some vehicles may not be long enough to secure a particular child seat.

Before purchasing, you should confirm that the child car seat is suitable for your car and that it can be safely installed in all seating positions you intend to use, such as the rear passenger seats or the third row in a people carrier. While manufacturer instructions provide guidance on installation, it is strongly recommended that the seat is professionally fitted when purchased, and that you are shown how to install it correctly yourself.

The RSA advises using retailers who are signed up to its Code of Practice. You can also seek advice from our child car seat experts by completing the online form provided here . In addition, the RSA ‘Check it Fits’ service offers a free, nationwide fitting service, and you can view upcoming locations here.

Check that the child car seat meets the EU standard - R129. If it does, you should see a yellow or orange sticker with an E mark and weight guidelines on the seat. 

Buying new is always the safest option.  Second-hand car seats can be safe, only if the following applies:

• You know and are completely sure of its history
• Must never have been involved in a crash (even if no damage is visible)
• It is within its expiry date (generally 5-10 years; check the exact expiry date which can be found on the sticker on the seat or embossed in the plastic shell)
• Must include all its original parts and instructions
• It comes from a trusted source (e.g. family or close friend)
• It complies with EU safety standards – check for the orange ‘E’mark label.  The label should indicate compliance with either ECE R44/04 (older standard) or R129 (i-Size), which is the new standard.

In Ireland, the key requirement is that the car seat must be approved under ECE R129 (i-Size) or ECE R44/04 (older standard, still valid if purchased before September, 2024) regardless of where the car seat was purchased.  

Ideally, fit your child’s car seat in the back seat. This means that they are away from airbags and the dashboard. If you must place the child car seat in the front, make sure that it is suitable for the child’s weight and height. 

Do not use a rearward-facing child car seat in the front seat where there is an active airbag.  Choose the biggest and strongest child to go in the front. 

 

Once you have followed the instructions on how to fit the child car seat, check the fit by:

• Movement test: Hold the seat at the base and try to move it side-to-side and forward.  It should not move more than about 2-3cm (1 inch).  If it wobbles more than that, it’s too loose.
• Installation check:

  For ISOFIX, make sure both connectors are fully clicked in (listen for an audible click and look for the green indicator).

• For seatbelt installation, ensure the belt is routed exactly as shown in the manual and pulled tight with no extra slack. 
• Visit our ‘Check it Fits’ service to get your car seat checked by one of our experts.  This service is a full-time, nationwide, free service and our experts will check the car seat is fitted correctly, and will answer any questions you might have.  Check the upcoming ‘Check it Fits’ locations here.

 

ISOFIX

• A built-in system that lets you attach a child car seat directly to your car’s chassis
• Uses metal anchor points instead of a seat belt
• Reduces the risk of incorrect installation
• Often includes visual indicators to confirm it’s fitted properly

 

i-Size

• A European safety standard for car seats (Also known as R129)
• Requires rear-facing car seats for longer (at least until 15 months)
• Classifies seats by child’s height rather than weight
• Includes improved side-impact protection testing
• Designed to work with ISOFIX systems for better compatibility
• Since September, 2024, only child car seats approved under R129 (iSize) standard  can be sold within the EU.  However, child car seats certified under the older R44 standard that are already in use remain legal and can continue to be used.

 

ISOFIX is how the seat attaches to the car, while I-Size is the safety standard the seat is built to meet.

The most common fitting errors are:

• Safety belt has too much slack in it causing the fitting to be very loose. 
• Safety belt not routed through child seat correctly. 
• Buckle resting against the frame of the child car seat, causing buckle crunch which may cause the buckle to open. 
• Handle on baby seat not positioned properly. 
• The child car seat is too big or too small for the child. 
• Child car seat not compatible with the car. 

Child car seat has exceeded the manufacturer’s recommended guideline for duration of use and is in bad condition.

Drivers have a legal responsibility to ensure that all passengers under 17 are appropriately restrained in the vehicle.

All children under 150cm in height or 36kg in weight must use a child restraint system (CRS) suitable for their height and weight while travelling in a car or goods vehicle (except taxis). 

It is illegal to place a rear-facing child car seat in the front passenger seat where there is an active airbag.

Children must travel in a rear-facing car seat until they are at least 15 months old.  Safety experts recommend keeping children rear-facing for as long as possible.

In Ireland, children must use an appropriate car seat or booster seat until they are at least 150cm tall, or 36kg in weight. 

Safety recommendation: Children should continue using a car seat until they reach 150cm in height, regardless of weight.  For older children, high back booster seats should continue to be used until the adult seat belt rests across the shoulder (not the neck) and across the pelvis (not the stomach).

Since 1 September 2024, child seats approved to Regulation R44 can no longer be sold by retailers, marketplaces, and e-commerce in the EU. 

Seats made available from these suppliers must now comply with Regulation R129. 

Child seats approved to R129 have undergone more rigorous testing and provide improved head and neck protection compared to seats approved to the previous R44 regulation. 

It's important to understand that consumers can still use a seat which conforms to R44 which was purchased prior to 1 September 2024.

There is no law against children sitting in the front seat as long as they are using a child restraint suitable for their height and weight. However:

It is illegal and highly dangerous to place a rear-facing child car seat in the front passenger seat where there is an active airbag. 

The back seat is the safest place away from airbags and the dashboard.

If a child must travel in the front passenger seat, ensure they are using a forward-facing car seat that is suitable for their height and weight.  Where possible, the biggest and strongest child should occupy the front seat.  Position the front passenger seat as far back from the dashboard as possible, as this could help reduce the severity of injuries should the airbag deploy in a collision.

 

Rear-facing child seat:  If a child is travelling in a rear-facing child car seat in the front passenger seat, the front passenger airbag must be deactivated.  It is illegal and highly dangerous to use a rear-facing child car seat in the front passenger seat where there is an active airbag.  If the airbag deploys, it can strike the back of the rear-facing seat with significant force, resulting in serious or fatal injuries.

 Forward-facing child seat or booster seat:  If a child is travelling in a forward-facing child seat or booster seat, the front passenger airbag can generally remain active, provided:

• The child is using the correct restraint for their height and weight

• The front passenger seat is moved as far back as possible to maximize the distance from the airbag.
• Both the vehicle manufacturer’s instructions and the child restraint manufacturer’s instructions permit the child set to be used in that seating position.

No. Taxi or bus companies are not obliged to provide child car seats for children. However, with the agreement of the company or driver, a parent may fit a child car seat for their child for the journey. This is particularly useful for young babies who are not able to sit up on their own yet, or children who are too small for the seat belt to be positioned correctly on their body.  

Some taxis and buses have shoulder belt adjusters on the seat belts that help position the seat belt correctly on a child's body. Parents and children should be shown how to use these correctly. 

Some public service vehicle companies also provide a facility where you can book or rent an appropriate car seat when booking your taxi trip. This should be done well in advance of a planned trip.  

It is very dangerous for a child to travel on an adult's lap in a vehicle, as they either have no restraint at all or they might get crushed between you and the seat belt in the event of a crash or hard braking. It is highly recommended that young babies who cannot sit by themselves use an infant carrier and young children use at least a booster seat / cushion to help position the seat belt correctly on their body.  

Buckle crunch is where the buckle of the seat belt is resting on the frame of the car seat. The movement of the car while travelling could cause the buckle to open. Also, on impact, the buckle could be broken causing the child car seat to become loose or detached in the car, giving little or no protection to the child in the seat. The webbing of the seat belt is much stronger and it should hold the seat in place. 

There is no specific road traffic regulation prohibiting the use of seat belt extenders in vehicles.  To ensure is the safety performance of a vehicle’s seat belts is not compromised, only type-approved devices should be used.   These can be identified by an “E” or “e” mark.  It is important to note that even if a device carries this mark, it may only be approved for use with certain vehicles or specific seat belt configurations.  To confirm which seat belt extenders are suitable for a particular vehicle (if any), the vehicle manufacturer should be consulted for guidance.

While using seat belt extenders to solve certain fitting issues, they can also create new safety risks like buckle crunch or buckles resting on soft parts of the body.  

Many aftermarket products (items not supplied with or specifically approved by the car seat manufacturer) have not been tested with your particular car seat and may affect its performance in a crash.  Examples of accessories that may be unapproved include:

• Head supports
• Strap covers or harness pads
• Toys that attach to the harness

You should only use accessories that come with the car seat or are explicitly approved by the car seat manufacturer for that specific model.

Anything that changes how the child harness, or seat functions can potentially affect collision protection.

Some children go through a phase of constantly slipping out of the child seat harness or safety belt, or incorrectly adjusting straps or seat belts, or releasing the buckle during journeys. This can be very worrying and frustrating for parents or guardians. It could be serious or even fatal for a child if the manufacturer guidelines are not carefully followed. 

 You should check that: 

• the harness or seat belt is adjusted correctly to your child, in line with the manufacturer’s guidelines 
• your child is comfortable

 Incorrectly adjusted harness straps may cause your child to be uncomfortable leading them to push straps off or open buckles.