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For Your Little One

For Your Little One Stepup I-Size Belted 2/3 Car Seat Booster Seat - Midnight Black (4-12 Years)

Good to know i-Size Belted Group 2/3 | No ISOFIX Needed | 4–12 Years
£34.99 £69.99 Save 50% Out of stock

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Suitable for children 100–150cm in height (approx. 4–12 years)

Group 2: 15–25kg (approx. 4–6 years) — Forward-facing
Group 3: 22–36kg (approx. 6–12 years) — High-back booster mode

Installation: 3-point seatbelt — compatible with virtually all vehicles, no ISOFIX required
Always check your child's height against the seat's headrest guide before use
1x Stepup i-Size Belted Car Seat (Midnight Black)
1x User Manual
✔ i-Size (R129) Certified — Exceeds current EU safety regulations
✔ Universal belted installation — no ISOFIX required, fits virtually any car
✔ Fits children 100–150cm (approx. 4–12 years) — Group 2 & 3
✔ Deep padded side-impact protection wings
✔ One-hand adjustable headrest — multiple height positions, no tools needed
✔ Premium breathable padding for all-day comfort
✔ Removable, machine-washable seat cover

For Your Little One Stepup i-Size Belted Group 2/3 Car Seat — Midnight Black. Designed to keep your child safe and comfortable from 100 cm to 150 cm (approximately 4 to 12 years), the Stepup i-Size Belted car seat is the last car seat you'll ever need to buy for this stage. Built to the latest UN R129 i-Size safety standard, it delivers superior side-impact protection and installs simply and securely using your car's existing seatbelt — no ISOFIX required.

Why Parents Love It

  • i-Size Certified (UN R129) — Exceeds current EU safety regulations for enhanced protection
  • Seatbelt Installation — Fits any car without ISOFIX, using your vehicle's existing 3-point belt
  • Fits 100–150 cm (approx. 4–12 years) — Grows with your child through Group 2 and Group 3 stages
  • Side-Impact Protection — Deep, padded side wings absorb and deflect impact energy away from your child
  • One-Hand Adjustable Headrest — Multiple height positions adapt quickly as your child grows, no tools required
  • Removable, Machine-Washable Cover — Easy to keep fresh and clean
  • Midnight Black Finish — Sleek, premium look that suits any car interior

Safety You Can Trust

The Stepup i-Size meets the stringent UN R129 regulation, which requires extended side-impact testing and a minimum height requirement — giving your child significantly more protection than older Group 2/3 seats. The belt-only installation means this seat is compatible with virtually any vehicle, making it a versatile choice for families with multiple cars.

Comfort for Every Journey

Thick, breathable padding and a one-hand adjustable headrest with multiple height positions mean your child can settle in comfortably whether it's the school run or a long motorway trip.

Specifications

  • Safety Standard: UN R129 (i-Size)
  • Child Height: 100–150 cm
  • Approx. Age: 4–12 years
  • Installation: Seatbelt (belted)
  • Facing Direction: Forward-facing
  • Cover: Removable & machine washable
  • Colour: Midnight Black
Belted booster car seat set with headrest, side wings, and green belt guides
For Your Little One Stepup I-Size Belted 2/3 Car Seat Booster Seat - Midnight Black (4-12 Years)
£34.99
£34.99 -50%
£69.99
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Order by 2.30pm for same-day dispatch

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Why you'll love it

Designed around family life

Discover the features, thoughtful details and benefits designed to make life with little ones easier.

i-Size Safety That Exceeds the Standard
01

i-Size Safety That Exceeds the Standard

The Stepup i-Size is certified to UN R129 — the latest and most rigorous car seat safety regulation in Europe. Unlike older Group 2/3 seats, i-Size requires mandatory side-impact testing, meaning your child is protected from impacts that traditional standards don't even test for. The belt-only installation means it fits virtually any car, making it an ideal choice for families without ISOFIX or those with multiple vehicles.
For Your Little One Stepup I-Size Belted 2/3 Car Seat Booster Seat - Midnight Black (4-12 Years)
02

Grows With Your Child From 4 to 12 Years

Covering 100 cm to 150 cm in height, the Stepup takes your child through both Group 2 and Group 3 stages in a single seat — no mid-stage upgrades needed. The one-hand adjustable headrest moves in seconds to match your child's growing height, while the deep padded side wings reposition automatically to keep protection exactly where it's needed at every stage.
Comfort Built for Real Family Life
03

Comfort Built for Real Family Life

The breathable, premium-padded cover keeps them cool in summer and cosy in winter — and when it needs a refresh, simply remove it and pop it in the washing machine at 30°C. The Midnight Black finish looks sharp in any car interior and hides everyday wear beautifully.
Designed for family life Comfort & practicality Made for everyday adventures

Customers praised this I-Size booster seat for being "sturdy and comfortable," with easy seat belt installation and a smart Midnight Black finish. The seat is practical for daily use and longer journeys, with many noting children settled in quickly. Delivery was fast and customer support was helpful when needed.

  • The Midnight Black colour looks smart in the car.
  • Really impressed with how sturdy this feels.
  • Used it on a longer journey and there were no complaints about comfort.
  • 5 stars: 38 (100%)
  • 4 stars: 0 (0%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
O
Oliver B.
Fast delivery

Ordered in the afternoon and it arrived really quickly. Well packed and the seat was exactly as described when it arrived. The Midnight Black colour looks smart in the car.

L
Leo M.
Fast delivery

Easy to fit, easy to buckle in and simple enough to move when needed. A really practical booster seat.

S
Sophie W.
Great quality

Really impressed with how sturdy this feels. My child is comfortable even on longer journeys and the seat feels well made.

R
Ruby G.
Great quality

We wanted something straightforward for our older child and this has worked really well. It feels sturdy and comfortable.

J
Jack H.
Simple to install

Used the seat belt to fit it and it was straightforward to set up. The instructions were clear and it was ready to use quickly.

A
Arthur H.
Simple to install

The black colour is simple and smart and the seat feels well finished. Pleased with the purchase.

E
Emily C.
Really pleased

Really pleased with the seat. It feels secure once fitted and is simple to use for everyday trips.

D
Daisy W.
Really pleased

Everything was straightforward from fitting to using it. My child settled into it straight away.

D
Daniel M.
Easy to use

Nice and straightforward to use. My child can get settled in easily and the black colour looks great in the car.

F
Freddie K.
Easy to use

Good everyday booster seat. It is comfortable enough for longer drives and does not feel too heavy.

G
Grace W.
Good booster seat

Good booster seat for an older child. It is comfortable, practical and does not feel too bulky in the car.

E
Evie W.
Good booster seat

Fitting it with the car seat belt was much easier than expected. Once in place it feels nice and secure.

T
Thomas E.
Very comfortable

We have used it on a longer journey and there were no complaints about comfort. It feels solid and secure.

A
Alfie B.
Very comfortable

Really happy with the quality. The seat looks smart in the car and feels sturdy enough for daily use.

C
Chloe R.
Looks smart

The Midnight Black finish looks really smart and goes well with our interior. Very happy with the overall quality.

I
Ivy C.
Looks smart

Customer support were really helpful when I had a question and got it sorted quickly. The seat itself is great too.

J
James T.
Good value

Good value for the price. Easy to fit with the car seat belt and simple to use day to day.

F
Finley T.
Good value

Nice simple design and a good fit in our car. My child finds it comfortable and easy to get in and out of.

M
Megan W.
Just what we needed

Just what we needed for our child. It fits nicely in the car and is easy to get buckled in.

L
Lily W.
Just what we needed

The Midnight Black finish is a good choice if you want something smart and easy to match with the car interior.

H
Harry T.
Nice sturdy seat

Feels nice and sturdy and the materials seem good quality. Pleased with how easy it is to use.

T
Theo P.
Nice sturdy seat

Very pleased with how quickly we had it set up. Straightforward instructions and a sturdy feel once fitted.

A
Amelia M.
Happy with the purchase

Happy with the purchase. The seat was simple to set up and my child seems comfortable in it.

R
Rosie C.
Happy with the purchase

Comfortable for my child and easy for us to use. It has made the school run much simpler.

G
George B.
Great for everyday use

Great for everyday school runs and longer trips. Easy to fit and easy to use once in the car.

A
Archie E.
Great for everyday use

Good solid booster and a nice size for the age range. Happy with the overall quality.

E
Ella D.
Easy seat belt fitting

The seat belt fitting was straightforward and the instructions made setup easy. It feels secure once fitted.

M
Millie S.
Easy seat belt fitting

Arrived promptly and in good condition. The seat was easy to fit and looks really smart.

O
Oscar W.
Really impressed

Very impressed with the overall finish. The seat looks good, feels sturdy and is comfortable for my child.

N
Noah M.
Really impressed

Easy to use and feels secure once fitted. We have been happy with it for everyday journeys.

I
Isla J.
Good quality seat

Good quality seat and a sensible size for an older child. It fits well without taking over the back seat.

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