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In a nutshell

A super stylish design with safety as a priority, the Sirona Gi from Cybex is ideal if you’re looking for an i-Size car seat that will stay with your child from their smallest days through to age 4 – but it does come with a high price tag

What we tested

Ease of installing
A star rating of 4.5 out of 5.
Comfort
A star rating of 4.5 out of 5.
Safety features
A star rating of 5.0 out of 5.
Style
A star rating of 4.6 out of 5.
Durability
A star rating of 4.5 out of 5.
Worth the money
A star rating of 4.6 out of 5.

Overall Rating

Pros
Rear-facing until 4
Swivel for easy switch between rear- and front-facing
Stylish design
Great ventilation
Multiple recline positions
Side-impact protection
Cons
Pricey
Have to buy ISOFIX base separately
Straps aren't magnetic
Might be too big for small cars

With a mid-to-high-end price tag of £279.95, the Cybex Sirona Gi i-Size spares no expense, fitting a breadth of safety features into this model, all while offering a stylish and sleek design. There's a wraparound ventilation system, side-impact protection, 5 recline settings and a 360-degree swivel, when used with the Cybex Base G ISOFIX base, £184.95.

If you're looking for an extended rear-facing car seat, you'll be pleased to hear the Sirona Gi i-Size offers rear-facing up to 4 years old.

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About our parent tester

Emily Hanson is a freelance education and parenting writer with previous experience as an early years specialist teacher (PGCE, M.Ed, Cambridge). With 2 daughters aged 3-and-a-half years and 6 months, she tested the Cybex Sirona Gi i-Size car seat in their mid-size Hyundai Kona, on short journeys to the shops right through to an hour’s drive.

2 pictures of baby in Cybex Sirona G car seat

What were your first impressions?

Straight out of the box, the Sirona Gi i-Size car seat looked great. It came already connected to the ISOFIX base, saving us a job.

Inside the box was the car seat and ISOFIX, and a card directing you to a digital instruction booklet. I was surprised to see no physical instructions but quickly noted that the QR code came with the box to take us to PDF versions. This was fine for us, but if you have limited internet at times this might cause an issue, especially if you need instructions or information while out on the road.

Thankfully, once accessed, the instructions were very clear. I liked that the packaging had no extras and was simply a very weighty card box which was easy to recycle (after my older daughter had turned it into a puppet theatre!).

How easy is the Cybex Sirona Gi i-Size to install?

Cybex are clear that an ISOFIX is the best way to go with fitting this, and it's the only option if you want to make the most of the 360-degree swivel.

The Cybex Base G ISOFIX base, which you need to buy separately, was incredibly easy to install in our car. It fits all along the edge of the seat and is quite substantial, which feels very safe, thoughit might pose an issue if you have a smaller car.

2 pictures of Cybex Sirona G car seat installed in car

How does the Cybex Sirona Gi i-Size compare to other car seats you've used?

We definitely prefer this seat to the one we have for our older child, particularly as it adjusts from these early months right through to 4, so that will save us money. There are bags of safety features with the Sirona Gi, and it’s incredibly stylish.

The swivel feature is also a great bonus, though this is becoming quite common for seats across the market in this age range, so with the higher-end price tag, I would expect this to be part of the seat.

What are the key safety features of the Cybex Sirona Gi i-Size car seat?

Safety feature-wise, the Sirona Gi has you set, particularly as the seat supports extended rear-facing up to the age of 4. Our younger child is 6 months, so this was a clear choice for her, while our older child (3-and-a-half years) fitted comfortably in the rear-facing position too.

The ISOFIX has a clear ‘green’ light, so you know when the seat is fitted correctly; the swivel function also features a green indicator so you know when that is fixed safely in position. The side-impact wings are another big safety feature, with integrated linear side impact protection to keep little ones as safe as possible on the move. Overall, it definitely feels robust, strong and safe.

How long is the Sirona Gi i-Size car seat rear-facing for?

The car seat fits a 3-month-old baby (around 61cm) through around a 4-year-old (105cm), and you can rear face the whole time. You also have the option of making this suitable for a newborn (40cm) with a separately bought insert. There is a max 20kg weight and 105cm height limit.

How comfortable is the Cybex Sirona Gi i-Size car seat?

My baby seemed very comfortable in the seat on our car rides, and our 3-year-old didn’t complain either when she tried it!

Does the Cybex Sirona Gi i-Size car seat rotate?

It does. The Sirona’s swivel feature has full 360-degree rotation, allowing easy onboarding on all sides of the vehicle. As we have 2 car seats, we focused on a 90-degree turn for onboarding, though 180 was very easy to use too.

We think it would also be brilliant if you have just one car seat, as older children could get in and out of the car from either side. A real game-changer compared to our older seats, which are not mobile and require quite a bit of shuffling to get our older child into.

Does the Sirona Gi i-Size car seat recline?

Yes, once the baby is in, the car seat can easily recline back for younger riders, or go more upright for older children – another reason the car seat has brilliant longevity. It offers 5 recline positions for both front and rear-facing.

What do you think of the straps on the Cybex Sirona Gi i-Size car seat?

The 5-point harness straps are easy to adjust and very robust, with a simple click mechanism and an easily adjustable pulley to tighten and loosen. One compromise we did find was that the straps themselves did not have magnetic sides, which our other car seats do.

This means when you are removing your child, the straps are easily 'grabable' and can be a bit fiddly to move out the way when undone (they flopped around a lot). Magnetic sides would make taking the baby out a bit easier.

How good is the headrest?

The headrest on the Cybex Sirona Gi i-Size car seat is very robust and adjusts as your child grows. My baby feels very protected and secure.

How easy is it to clean the Sirona Gi i-Size car seat?

This Cybex car seat is really easy to clean with detachable covers which are machine washable at 30°C – great for the odd sick-up or poonami which we do experience on a regular basis in this house! We had the Sirona in a dark grey shade, so marks were easily covered, though lighter colours may stain more easily.

Does it have a sun hood?

No, the Sirona Gi doesn’t come with a sun hood, though I wouldn’t really expect a seat of this type to. I would usually only expect an infant seat, which comes as part of a travel system, to have a sun hood.

How easy is the Cybex Sirona Gi i-Size car seat to carry around?

Size-wise, this is definitely a seat for a family car. It is pretty heavy – 6.5kg without the base – and removing the ISOFIX from the seat itself is a bit fiddly. We rarely were in the position to take it in and out of the base, so this didn’t pose a problem for us, but you might find it a bit bulky if you’re regularly swapping the seat between cars.

Is the Cybex Sirona Gi i-Size car seat big enough for a growing child?

This is a very big yes. The Sirona Gi is brilliant at being a seat that will grow with your little one. We fit our 50th percentile 6-month-old daughter in there comfortably, and our 3-year-old, who weighs about 16kg, still fits comfortably, and should still have room for another 6 months, I would anticipate (which takes her up to 4, and likely the 20kg limit).

What accessories can you buy for the Sirona Gi i-Size car seat?

Cybex Base G ISOFIX base, £184.95. Essential if you want to use the 360-degree swivel.
Sirona G Line Newborn Inlay, £44.95. Essential if you want to use this on a newborn, or any child between 40 and 61cm in length.
Summer cover, £54.95
Cup holder, £29.95

What are the repair options like for the Cybex Sirona Gi i-Size car seat?

We like that Cybex offers a 3-year warranty on its car seats, which covers the majority of this product’s life phase for one child. It notes that if there is a fault with the seat, you need to return it to the retailer, and the same goes if you need to get replacement parts.

Who would the Cybex Sirona Gi i-Size car seat be most useful for?

I think the Sirona Gi i-Size would be most useful for families wanting a long-lasting, durable car seat without sacrificing on style. We love that our little one will stay in the Sirona until she’s ready for school, so there’s no need to think about sizing up before she hits 20kg.

What would you have liked to know before purchasing the car seat?

We would have liked to know that the straps didn’t have magnetic sides, but it wouldn’t put us off recommending it to a friend.

Is the Cybex Sirona Gi i-Size car seat worth the money?

At £279.95, it’s certainly on the higher price side when it comes to car seats, but based on the longevity of the product, we think it is. Just remember you'll need to factor in the additional cost of the £184.95 base if you want to use the Sirona Gi with ISOFIX.

Where can I buy the Cybex Sirona Gi car seat?

It is available from Cybex, Mamas & Papas and John Lewis.

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MadeForMums verdict:

Overall, we really liked the Sirona Gi i-Size car seat. The level of safety is reassuring, the swivel feature is very handy, and we know it will last our family for many years to come. It’s stylish, supportive, and a great choice for a long-term seat, particularly if you are keen on extended rear-facing. Yes, it's pricey, but I think it's a worthwhile investment, as long as you have space in your car.

Emily Hanson