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Junior Maxi™ i-Size R129

Lightweight Highback Booster Car Seat


From 100-150cm (approx. 3.5 to 12 years)

New! Sale Best Seller

Junior Maxi™ i-Size R129

Lightweight Highback Booster Car Seat


From 100-150cm (approx. 3.5 to 12 years)


Out of Stock Online
Only %1 left

Buy now

Free shipping on orders over €60

Delivery usually in 2-5 business days


2-Year Warranty

Ready to ride with i-Size and R129 for years to come

Our best-selling highback booster is now i-Size and R129 ready! Junior Maxi i-Size R129 provides extra safety for your growing child without sacrificing on comfort. Packed with features like enhanced side impact protection, premium padding and a 10-position headrest, this lightweight car seat is sure to be a hit for both parents and kids alike.

All The Features You Will Love

Boy sitting in Graco Junior Maxi i-Size R129 highback booster with i-Size and R129 logos.

Safety above all else

Our parent-favourite Junior Maxi R44 highback booster has been adapted to meet i-Size and R129 standards. This means Junior Maxi i-Size R129 has undergone more extensive side impact testing and is compatible with any i-Size approved vehicle, reducing the risk of incorrect installation.

Mum adjusting the headrest as boy sits in Graco Junior Maxi i-Size R129 highback booster.

Grows and goes

Junior Maxi i-Size R129’s 10-position headrest ensures your growing child is always properly fitted.

Boy putting his hand on the padded seat of Graco's Junior Maxi i-Size R129 car seat.

Extra comfy

No matter the distance, this thoughtfully designed highback booster seat delivers comfort on each and every ride.

Mum carrying the lightweight Junior Maxi i-Size R129 highback booster.

Pick up and go

You can easily move this highback booster between vehicles for hassle-free journeys.

Installation Video

Is Junior Maxi i-Size R129 Right for Me?


Graco's remarkable Junior Maxi i-Size R129 highback booster is designed to keep growing big kids safe and comfy. This car seat meets the EU’s latest R129 safety standards and is i-Size certified, which means that it will correctly fit in any i-Size approved vehicle. Equipped with enhanced side impact protection, this booster seat provides an additional layer of security for your big kid.


You can effortlessly adjust this highback booster’s 10-position headrest to ensure your growing child always has proper head and neck support. The premium padded seat offers extra comfort and the two retractable cupholders keep drinks within reach so your child always has a pleasant ride — no matter how long the trip. Weighing in at only 3.4kg, Junior Maxi i-Size R129 is easy to install and move between vehicles, making it ideal for families on the go. To minimize the risk of using the seat belt incorrectly, the open-loop belt guides keep the seat belt correctly positioned across your growing child’s body.


Suitable from 100 to 150cm (approx. 3.5 to 12 years), Junior Maxi i-Size R129 comes with removable and machine-washable covers, making cleaning a cinch. Take this highback booster with you on every adventure and let your child experience the world in uncompromised safety.

All Features

- i-Size and R129 certified
- Enhanced side impact protection safeguards your child’s head and neck


Ease of Use
- Lightweight at only 3.4kg, making it easy to move between vehicles for hassle-free journeys
- Open-loop belt guides help ensure proper seat belt positioning
- Machine-washable covers for easy clean up


Child Comfort
- 10-position headrest provides proper support for your child’s head and neck
- 2 retractable cupholders keep drinks, gadgets and goodies right within reach
- Premium padded seat for enhanced comfort
- Forward facing highback booster from 100 to 150cm (approx. 3.5 to 12 years)

Product Length
Product Width
Product Height
Product Weight
Package Includes

(1) Junior Maxi i-Size R129 highback booster car seat

(1) instruction manual


What is the difference between Junior Maxi R44 and Junior Maxi i-Size R129?
There are currently 2 different car seat standards in the EU. R44 (legally known as ECE R44/04) car seats are divided into groups based on weight, with some covering multiple groups. Eventually, R44 car seats will no longer be available for purchase, but these seats are still safe to use. Junior Maxi R44 is based on these standards.


Junior Maxi i-Size R129 meets the new R129 (legally known as ECE R129) standards. The main differences in these standards are that car seats are based on your child’s height and undergo more side impact testing. Junior Maxi i-Size R129 is based on these standards. You can learn more about car seat standards and help figure out which car seat is right for you in our car seat buying guide.


Does the back of Junior Maxi i-Size R129 detach to use as a backless booster?
Junior Maxi i-Size R129 cannot be detached for use as a backless booster. We have backless boosters such as EverSure Lite R129 and Booster Basic R129 for you to choose from.


Can I machine wash Junior Maxi i-Size R129’s seat covers?
Yes, you can wash the covers in your washing machine with cold water only on the delicate cycle. Drip dry and do not use bleach.


What is the maximum height and age for Junior Maxi i-Size R129?
This car seat can be used until your little one is your big one, up to 150cm or approximately 12 years of age.


How do you safely keep Junior Maxi i-Size R129 in your vehicle when not being used?
To ensure the safety of you and anyone else in the vehicle, we recommend buckling in the highback booster even when there is no kid in it. This will keep it from being thrown from the seat in the event of a collision.

Recommended Use

This car seat is suitable from 100-150cm (approx. 3.5-12 years).

Care & Maintenance

To wash the covers: machine wash in cold water only on delicate cycle 30 degrees and drip dry. Do not use bleach.


Metal and plastic parts: clean with mild soap and cool water. No bleach or detergents.

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