Key points
- Car seats and booster seats help protect your child from serious injury while travelling in a car.
- There are best-practice recommendations for car seats to ensure children are kept as safe as possible. These recommendations are not always the same as the law.
- It is important to find out the safest category of car or booster seat for your child.
- Babies and young children are safest in a rearward-facing car seat. Your baby should stay rearward-facing for as long as they fit – ideally until two to three years of age.
- Shoulder markers are a good way to check if your child is safe in their car or booster seat or if they have outgrown it.
- The ‘5 step test’ is a series of questions that checks whether it is safe for your child to travel with an adult lap-sash seat belt only. Your child must pass all five steps to be considered safe without a booster seat.
- Most children will not pass the ‘5 step test’ until they are aged ten to twelve years old.
Why are car and booster seats so important?
Road crashes are the major cause of accidental death for children aged under 15 in Australia. Each year in Victoria, hundreds of children are involved in car crashes. During a car crash, a child’s risk of serious injury is much higher if they are:
- unrestrained in the car (not in a car seat, booster seat or adult lap-sash seat belt)
- not restrained correctly (in a car or booster seat not suitable for their size)
- travelling in the front seat of the car.
Car and booster seats protect your child from serious injury while travelling in a car. They do this by:
- securing your child to their seat
- helping absorb the impact of a crash to protect your child's head, neck and body
- restraining your child with straps that rest on strong bones like their shoulders and hips instead of their neck and abdomen.
You should always ensure your child is in the correct car or booster seat for their size – even for short drives. The correct seat might change in different cars.
Which car or booster seat is best for my child?
There are three main categories of child car and booster seats:
- Rearward-facing child car seats
- Face the back of the car
- Support the back, head and neck
- Have a built-in harness.
- Forward-facing child car seat
- Face the front of the car
- Support the back, head and neck
- Have a built-in harness.
- Booster seat
- Face the front of the car
- Support the back, head and neck
- Do not have a built-in harness – use an adult lap-sash seatbelt.
Your child should always travel in a restraint that matches their size, not their age. Do not move your child into the next restraint category too quickly – even if age-based laws allow it.
Changing child car restraints
Moving your child to the next car restraint category too early increases their risk of serious injury or death in a car crash.
Most Australian car restraint laws are age-based. However, The Royal Children's Hospital (RCH) strongly recommends following the national expert guidelines for safest restraints and choosing a restraint that fits your child's size rather than their age.
Size-based recommendations will keep your child in each car seat for longer but also keep them safer.
Wait until your child outgrows their car or booster seat before moving them into a bigger one. Then, try all options in your child’s current restraint category before moving them to the next category. For example, look for a larger car seat before moving
your child into a booster seat.
Visit the Transport
Victoria website to read the current laws and recommendations on car and booster seats in Victoria.
Rearward-facing car seat
Your baby must be in a rearward-facing car seat or capsule from birth. This restraint supports their head and neck while travelling and greatly reduces the impact of a crash on their body.
There are different types of rearward-facing car seats, such as infant capsules and combination car seats, which change from rearward-facing to forward-facing.
You should adjust and fasten the straps of the rearward-facing car seat or capsule on every trip.
When to move to a forward-facing car seat
Your child is safest when travelling in a rearward-facing restraint. They should stay rearward-facing as long as possible – ideally until they are two to three years old. You should only move your child to a forward-facing car seat when they outgrow the
maximum size limit.
Rearward- and forward-facing car seats compliant with the Australian and New Zealand Standard AS/NZS 1754 usually have shoulder height markers. These markers are a good way to check if your child is safe in their restraint or has outgrown it.
When your child outgrows their rearward-facing car seat, try to get a larger rearward-facing car seat rather than moving them forward-facing too early.
| Age |
Australian laws |
Expert safety recommendation |
| Under six months |
Rearward-facing only. |
Rearward-facing car seat or capsule only. |
| Six months to four years |
Rearward- or forward-facing car seat with a harness. |
Rearward-facing car seat for as long as possible. Use size, not age, to decide when to change restraints. Rearward-facing car seats are available to fit children up to two to three years of age. |
When to move to a booster seat
Your child should be in a forward-facing car seat until they outgrow the maximum size limit – as shown by the seat’s shoulder height markers. This is because a forward-facing car seat’s inbuilt harness protects your child more than a booster seat with
an adult seat belt.
The average Australian child will not outgrow a forward-facing car seat until they are eight, and some children may be older.
When your child does outgrow their forward-facing car seat, it is time for a booster.
| Age |
Australian laws |
Expert safety recommendation |
| Four to seven years |
Forward-facing car seat with a built-in harness or booster seat. |
Forward-facing car seat with inbuilt harness for as long as possible. Use size, not age, to decide when to move to a booster seat.
|
| Seven years and older |
Booster seat or adult lap-sash seat belt only. |
Booster seat until child passes the ‘5 step test’ (details below). |
When to move to an adult seat belt only
As with moving to a forward-facing car seat, your child should be in a booster seat until they outgrow the maximum size limit on the shoulder height markers. A booster seat protects your child more than an adult lap-sash seat belt alone; the risk of serious
abdominal, head, neck and spinal injuries increases up to 3.5 times for a child who fits in a booster seat but does not use one.
Different booster seat models fit children of various sizes; try to choose one that will fit your child for as long as possible. Boosters are available to fit most children until they are 10 to 12 years old.
When you think your child has outgrown their booster seat, you should only move them to an adult car seat if they pass the ‘5 step test.’
The ‘5 step test’
The ‘5 step test’ will help you check whether your child is big enough to use an adult lap-sash seat belt only. The steps are:
- Can the child sit with their back against the vehicle seat?
- Do the child's knees bend over the edge of the seat?
- Does the sash part of the seat belt sit across the middle of the child's shoulder (not on their neck or out near their arm)?
- Is the lap part of the seat belt sitting low across the child's hips, touching their thighs?
- Can the child stay safely seated like this for the whole trip?
The answer to all five steps must be ‘yes’ before it is safe for your child to travel without a booster seat.
On average, Australian children are not big enough to pass the ‘5 step test’ in most cars until they are 10 or 11 years old.
Remember: whether your child passes the ‘5 step test’ depends on both their size and the car they are travelling in. For example, some cars have large backseat areas. Test your child in every car before they travel.
When to move to the front seat
Your child should sit in the back seat until they are aged 13 or older. This is because the risk of injury to children aged 12 and under is nearly double in the front seat compared to the back.
Installing a car seat
Car and booster seats only protect your child if they are installed correctly. The RCH strongly recommends having all car restraints checked by a professional fitter to ensure they are safe and secure.
Important tips for car seat safety
- Buy or rent a car seat that complies with the Australian and New Zealand Standard AS/NZS 1754. It is illegal to use an overseas model or restraint that does not meet this standard.
- Always follow the car seat manufacturer’s instructions and shoulder markers to ensure the restraint fits your child’s size.
- Fasten the straps of a forward-facing car seat every time your child travels in it.
- Check your child’s car seat or booster regularly and adjust it as they grow.
- Always ensure you buckle your child in properly, using the correct car restraint for their size – even if it is only a short trip.
Common questions about car and booster seats
My child is more comfortable facing forward in the car; can I move them from rearward to forward-facing?
Car seats are about safety in a car crash and avoiding death and serious injury – not about comfort. The only safe reason to move a young child from rearward-facing to forward-facing is because they no longer fit in a rearward-facing car seat.
Do car seats expire?
KidSafe, the Child Accident Prevention Foundation of Australia, recommends using car seats less than 10 years old from the date of manufacture. Car seat materials wear over
time, offering less support and protection. Do not use a car seat with splits, cracks, stress marks, or frayed and worn straps. If a car seat has been involved in a crash, you should not use it again – even if it does not look damaged. It
could be broken inside. Some companies will exchange a crash-damaged seat for a new one.
Can I use a booster cushion instead of a booster seat?
Booster cushions differ from booster seats as they do not have back or head support, and you cannot anchor them to the car. Unlike booster seats, booster cushions do not protect your child’s sides or head in a car crash. Booster cushions are not
recommended and cannot be legally used in Australia.
What if my child has outgrown the restraint they are currently in?
When your child outgrows their car or booster seat, it does not necessarily mean moving them into the next restraint category is safe. They may just need a larger size of the same restraint. For example, if your child is six months old and outgrows
their rearward-facing infant capsule, it is safer to buy a larger rearward-facing car seat than move them forward-facing too early.
How do I know if my car seat meets Australian safety standards?
All car seats sold in Australia that comply with the Australian and New Zealand Standard AS/NZS 1754 will be clearly labelled on the packaging and on the seat itself. If your car seat has this label, it meets minimum safety requirements and is
safe to use. You do not need to rely on additional safety ratings, expensive brands or special extra features. Car seats or boosters purchased overseas may not meet Australian safety standards.
My child does not want to use a booster seat, but they still fit the size recommendation. What should I do?
The answer to all five questions of the ‘5 step test’ must be ‘yes’ before it is safe for your child to move into an adult seat with a lap-sash seat belt. While it is normal for your child’s friends to influence them, you are responsible for their
safety. Take the time to speak with your child about why they must stay in a booster seat. Always try to prioritise safety over convenience.
Can I use the booster seat built into my car, or is it safer to buy a separate booster seat?
Victorian laws allow children four years or older to use built-in booster seats. While built-in booster seats may be convenient because you do not need to get them installed, they may not protect your child’s back or head as much as a separate
booster seat. Check with relevant regulatory bodies for your state's car seat safety laws for built-in booster seats.
Does my baby need a car seat in a taxi or rideshare service like Uber?
In Victoria, the law does not require taxi drivers to provide car or booster seats to passengers. If your child is under one year old, they must travel in the back seat of a taxi, and an adult must hold them but not share their seatbelt. If your
child is over one year old, they must travel in their own seat in a taxi with a separate seat belt if there is no car restraint. Victorian taxis legally need an anchor fitting for passengers to use their own child car restraints if they choose to.
The rules are different for rideshare services like Uber. Rideshare cars have to follow the standard Victorian road rules for private cars. This means your child must be in a legally compliant car or booster seat in a rideshare car until they
are seven years old.
If you live outside of Victoria, make sure to check your state’s laws before travelling.
It is always safest to put your child in a suitable restraint whenever travelling in a vehicle. This may mean taking your own car seat with you and knowing how to install it in another vehicle.
This podcast is also available in audio format below, and on Apple Podcasts and Spotify.
Bonus episode: Car seat safety
For more information
Developed by The Royal Children's Hospital Trauma department. We acknowledge the input of RCH consumers and carers.
Reviewed April 2025.
Please always seek the most recent advice from a registered and practising clinician.