Cybex Sirona S i-Size – The 360° rotating car seat for comfort and safety

With babies come car seats. Sadly our little sprog has never been a fan of the car journey. Having a small car means the ride hasn’t always been super smooth, but part of the problem has also been the general comfort provided by the car seats we had. We were lucky enough to be given a lot of hand-me-downs when the little one was born. However, not every hand-me-down is a useful thing for your baby. After a lot of crying and even more research, we decided to get a new car seat for the little one. Since we have a fussy little bean, we decided to be fussy in our needs too, and go for a slightly upmarket car seat. We chose the Cybex Sirona S I-Size, for the safety it offers, plus the 360 rotation as an added feature.

Cybex Sirona S I-Size Car Seat – Features and Specs

  • Suitable from birth – 105 cm, up to approx. 4 years
  • Rearward facing up to 105 cm, approx. 4 years
  • Group 0+ – 1
  • Secured using the car’s ISOFIX system and requires no further fastening
  • 360° rotation with easy entry position
  • Driving direction control (DDC) – Prevents turning the car seat to forward position before the child is above 76cm.
  • Energy reduction technology (ER-Tech) in forward-facing position (from 16 months and 76 cm)
  • Integrated L.S.P. system
  • Height-adjustable headrest
  • 8 recline positions
  • Newborn inlay included
  • Free 2 year guarantee


Since the car seat requires Isofix to attach it to your car, it is advised that you check the compatibility of your car with the car seat before you buy it.

This can be done via the Cybex Sirona S I-Size website. Scroll past the features till you get to the compatibility section.

Generally, most cars sold in the UK post-2008 have it added.

Buying options


Since this isn’t cheap, I tried to find as many options as I could possible find. I looked at all the usual suspects: Mothercare, John Lewis, Amazon, and many other retailers. I found that the best price I could find was £300, at most places. We went with Mothercare, mostly because their staff had been super helpful. This had to be a pre-order, as they didn’t have it in stock, so I paid for it from the comfort of my home and laptop. A useful thing to know is that if you pay online, Mothercare also accept PayPal, which is something I like to use.

Why the Cybex Sirona S I-Size

There were a few reasons to choose the particular car seat as well as model we chose.


Most car seats are rated for weight, and that is where the safety setup is focused on. With I-Size, you have both weight and height in consideration. Of course, for most kids who are average, this shouldn’t be a worry. The extra safety definitely gives you more peave of mind.

360° Rotation

Putting our little one in the car has never been an easy job. At just past 1, she is starting to get heavy enough that it can be a serious faff. Having the option to rotate the seat outwards while we put her in makes it super easy for us.

DDC (Driving Direction Control)

The car seat comes with an adjustable headrest for the height of your child. While the child is under 76cm, it prevents the seat from turning forward. This ensures that they face rearward as long as possible, hence giving them extra safety.

Other safety features

It also comes with lots of cushioning and other safety features, all tested to the latest European standards.

Installation Indicators

When the seat is being installed or adjusted to its rear/forward position, clear indicators tell you if the car seat is installed properly or not.

Instruction Manual

Weirdly, the car seat does not come with an instruction manual. There are instruction stickers dotted around the car seat, but in usual Ikea fashion, they are highly graphic and not very clear.

However, you can download the instruction manual from the Cybex website by clicking this website. Other language options are available via the product website.

How to install the Cybex Sirona S I-Size

As mentioned, the Cybex Sirona S I-Size car seat does not come with any instruction manual or installation instructions. So here is a list of things you need to do.

Take off any packaging

This one is obvious, but you might want to do that before you try and install the car seat.

Ensure the car seat area is clean

Ensure the car seat area is clear. Also make sure that the seat in front has been pushed as far forward as possible and seat has been reclined forward to give you as much space as possible. This is of particular importance for smaller cars.

Start with the Isofix

On both sides of the car seat, at the bottom, you will see these sliding mechanisms. These slide the Isofix fixings out from the car.

Press both ends to move it.

Once you slide it in, you will hear a click sound. You will also notice that the indicator seen within the button will go from red/grey to green. Do this on both sides.

Set up the vertical bar

Excuse the messy car! The vertical bar is taken down by pressing and sliding the button on it. Push it as far down and then angle it away from the car seat. As it clicks into place, you will also notice the indicator for it go green. In the picture above, that is the top one.

This required bit of a knack but clicked into place once the angle was correct.

Take out the door protection

On the top side of the car seat is the door protection. That is taken out by pressing the button on th side. This is a small bit of plastic that faces towards the door and helps protect the car seat from any side impacts.

Adjust the headrest

The headrest can be adjusted by putting your fingers behind the slot in the car seat. It can be adjusted to up to 106cm of height. Anything below 76cm and the car seat can only be rotated rear and not forward.

Adjust the front seat

This is important to ensure that you set it in such a way that allows you to rotate the child seat as needed. You should be able to push it back a bit. I pushed mine quite far back, but ended up leaving the recline a bit straighter to allow the Cybex to be rotated as needed.

Remove the infant insert (if needed)

Behind the car seat is also the infant insert to give your child more support. If your child is above 61cm, this can be removed. This is attached using velcro to behind the seat and once you figure this bit out, it comes out easily.

Inserting your child and moving the seat

Ideally you want the seat to be facing you when you insert your child into the car seat. The standard strap system allows you to put them in, and if you press the silver button shown above, you can adjust the straps loose. To make them tight, simply pull on the strap below the silver button.

To adjust the recline, insert your hand into the slot below and press the button to adjust the recline as needed.

The same button is used to rotate the car seat the full 360 degrees. It must be remembered that the car seat only rotates when it is fully vertical.

How to remove the Cybex Sirona S I-Size

Once you know how to install this, the removing part is reasonably easy.

Start with pressing the button on the vertical bar to lift it up.

Then simply press the buttons on the sliding Isofix bars on both sides to remove it from both ends.

This should free up your car seat to be removed from the car, and moved around.


As already mentioned, plenty of comfort and padding is offered by the car seat. We have done two longish trips with this one, and the wee one has fallen asleep in both instances on the way back. We did need a bit of help from some videos, but it seems to be a good solution so far regarding the travel with the little one.


£300 is a lot to spend on anything, but with all the safety, the extra features as well as adjustability and comfort, the Cybex Sirona S I-Size has been a great car seat for us so far.

I will endeavour to update this if my findings change.

Check out other products we have tried for our little one by clicking on the baby section on our website.


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4 thoughts on “Cybex Sirona S i-Size – The 360° rotating car seat for comfort and safety

  1. The seat does come with a manual. It’s actually in the seat.
    It’s behind the seat cushion very close to where the newborn insert is velcroed on. There is a plastic flap and the manual is sitting inside it’

  2. Hi, I can only seem to get two positions in rearward facing. Upright and a slight tilt. Anyone know how to get the other three? Is there a special knack? Thanks.

    1. Hey, just tried ours, and while it only stops at certain points and not wherever you leave it, but it definitely offers more than 2 points. Not sure what the knack is apart from maybe having it all the way to recline and push it back up from there? It’s how I did it but not sure if that’s needed.

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