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FlexiGrow™ R129

2-in-1 Harness Booster Car Seat


From 76 to 145cm (15 months to approx. 12 years) 

New! Sale Best Seller

FlexiGrow™ R129

2-in-1 Harness Booster Car Seat


From 76 to 145cm (15 months to approx. 12 years) 


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€139.00 €139.00

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2-Year Warranty

A 2-in-1 car seat with enhanced comfort

Get ready to ride in comfort for years to come with FlexiGrow R129. This 2-in-1 harness booster seat meets the EU’s R129 standards and will keep your child safe and secure thanks to the enhanced side impact protection and reinforced steel frame. As your child grows, FlexiGrow R129 is ready to adapt and provide perfect levels of comfort on every journey.

All The Features You Will Love

Little boy buckled in Graco FlexiGrow™ R129 2-in-1 harness booster and laughing with R129 certified logo

Safety above all else

This harness booster meets the EU’s latest and greatest R129 standards. This means FlexiGrow R129 has undergone more side impact testing to ensure your child is safe on every adventure.

Split screen of Graco FlexiGrow™ R129 2-in-1 harness booster car seat in harness mode and in highback booster mode

Grows with your child

Get more longevity out of this car seat thanks to the 2 forward-facing modes. From 76 to 105cm (15 months to approx. 4 years), use FlexiGrow R129 as a harness booster. When your child reaches 100cm (approx. 3.5 years), you can transition to highback booster mode until your big kid reaches 145cm (approx. 12 years).

Little boy sitting and smiling in Graco FlexiGrow™ R129 2-in-1 harness booster car seat featuring the Safety Surround™ Side Impact Protection tag

Enhanced protection

This car seat is equipped with Safety Surround™ Side Impact Protection, which wraps around your child and provides enhanced head and body protection.

Graco FlexiGrow™ R129 2-in-1 harness booster car seat with arrows emphasizing the expanding sides for your growing child

Grow and goes

FlexiGrow R129 adapts as your child grows both up and out. When the headrest is raised, the side wings of the car seat simultaneously expand, keeping your precious cargo comfortable and safe for as long as they ride in this harness booster.

Installation Video

Is FlexiGrow R129 Right for Me?


This feature-packed, 2-in-1 car seat offers you years of use without sacrificing comfort. FlexiGrow R129 goes from harness booster mode (76-105cm) to highback booster mode (100-145cm), growing with your child from toddler to pre-teen. When you raise the 9-position headrest and no-rethread harness, the car seat’s side wings expand to properly fit your child at any stage.


FlexiGrow R129 meets the EU’s latest R129 safety standards, which means it has undergone more side impact testing. For even more peace of mind, the car seat’s frame is reinforced with steel and there’s even more head and body protection thanks to Safety Surround™ Side Impact Protection.


To ensure correct installation whether you’re in harness or highback booster mode, FlexiGrow R129 comes with an integrated belt lock-off and open-loop belt guides. When your big kid is ready for highback booster mode, conveniently stow the harness in the car seat’s integrated storage.


Your growing child will love the 4-position recline, soft cushioned insert and plush fabrics that make every ride an enjoyable one. Their favourite goodies and snacks are close by thanks to the handy mesh side pockets. When life gets messy, remove the car seat’s covers and toss them in the washing machine.

All Features

- R129 certified
- i-Size certified in highback booster mode
- Safety Surround™ Side Impact Protection wraps around your child for enhanced protection
- Steel reinforced frame for extra durability and safety
- Integrated belt lock-off for easier seat belt installation in harness booster mode
- Open-loop belt guides help ensure proper seat belt positioning in highback booster mode
- 5-point harness that easily adjusts with one hand


Ease of Use
- 2-in-1 forward-facing car seat easily goes from harness booster to highback booster
- No-rethread harness allows you to easily adjust the harness and headrest together as your child grows
- Integrated harness storage allows you to store the harness away without fuss
- Machine-washable covers for easier cleanups


Child Comfort
- Adjustable width adapts as your child grows both up and out
- 4-position recline for more enhanced comfort
- 9-position headrest provides proper support for your child’s head and neck
- Mesh side pockets keep goodies and snacks right within reach
- Soft cushioned insert included
- Plush fabrics for comfort on each and every ride


- Forward-facing harness booster mode from 76 to 105cm (15 months to approx. 4 years)
- Forward-facing i-Size highback booster mode from 100 to 145cm (approx. 3.5 to 12 years)
- Installs with your vehicle’s seat belt

Product Length
Product Width
Product Height
Product Weight
Package Includes

(1) FlexiGrow R129 car seat

(2) harness pads

(1) padded insert

(1) crotch pad

(1) instruction manual


What EU safety standards does FlexiGrow R129 meet?
There are currently 2 different car seat standards in the EU: R44 and R129. 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.


FlexiGrow R129 meets the new R129 (legally known as ECE R129) 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.


What are the differences between harness booster mode and highback booster mode?
FlexiGrow R129 is a 2-in-1 harness booster, which means you will get several years of usage in one car seat. In harness booster mode, the vehicle’s seat belt ensures the car seat stays in place while the integrated 5-point harness keeps your growing rider properly positioned. In highback booster mode, the integrated 5-point harness is removed and the vehicle’s seat belt keeps the child safely in place.


How do I switch FlexiGrow R129 from harness booster mode to highback booster mode?
When your child reaches 100cm (approx. 3.5 years), you may transition from harness booster mode to highback booster mode. Your child can stay in harness booster mode as long as their shoulders comfortably fit when the harness is at its highest setting. For a step-by-step guide on how to store the harness to switch to highback booster mode, we recommend you watch this video.


What is the maximum height and age for a child to ride in FlexiGrow R129?
This car seat can be used until your little one is your big one, up to 145cm or approximately 12 years of age.


Does FlexiGrow R129 need to be installed with a base?
No, FlexiGrow R129 is not compatible with any base and is installed using your vehicle’s seat belt.


Can I machine wash FlexiGrow 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.

Recommended Use

This car seat is suitable from 76 to 145cm (15 months to approx. 12 years)


Forward-facing harness mode: suitable from 76-105cm using the 5-point harness to secure your child inside the car seat.  To install the car seat into your vehicle, use the 3-point safety belt.


Forward-facing highback booster mode: suitable from 100-145cm.  Secure your child in the car seat using the vehicle's 3-point safety belt.

Care & Maintenance

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


To clean the harness straps: surface wash only with mild soap and a damp cloth. Do not immerse the harness straps in water, doing so may weaken the straps.


Remove the child restraint from the vehicle seat if not in use for a long period of time.


Inspect and clean harness buckle from time to time to remove any objects or debris that could prevent correct installation.


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

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