Discover the new CYBEX Sirona S at Chelsea Baby: a premium rotating toddler car seat designed for extended rear-facing travel from approximately three months to 4.5 years. Combining one-handed 360° rotation, CYBEX GrowTech comfort and enhanced side-impact protection, Sirona S offers safer, more comfortable travel throughout the toddler years.

Suitable for children from 61–105 cm and up to 20 kg, the Sirona S installs onto the separately available CYBEX Base S. Add the optional Sirona S-Line Newborn Inlay to extend use from birth and 40 cm.

Shop the CYBEX Sirona S online or visit Chelsea Baby in the Midlands for expert car-seat advice, vehicle compatibility guidance and a personal demonstration.

Extended Rear-Facing Travel Up to 4.5 Years

The CYBEX Sirona S is designed to keep children rear-facing for longer, supporting safer travel from approximately three months through to 4.5 years.

In a frontal collision, the rear-facing seat shell helps distribute impact forces across a larger area while supporting the child’s head, neck and upper body. CYBEX states that rear-facing travel in Sirona S can provide up to 50% better protection than using the same seat forward-facing, based on its internal frontal-impact testing.

Sirona S can remain rear-facing throughout its complete 61–105 cm usage range, up to a maximum child weight of 20 kg. Forward-facing use is permitted only once the child is at least 15 months old and 76 cm tall, although rear-facing travel is recommended for longer where practical.

One-Handed 360° Rotation

Smooth 360-degree rotation allows the CYBEX Sirona S to turn towards the open vehicle door, making it easier to place your child into the seat and correctly adjust the harness.

The rotating design reduces the need to lean and twist into the vehicle, while the Easy-In crotch pad stays upright to prevent the buckle disappearing beneath the child. Magnetic belt holders keep the harness straps positioned at the sides of the seat, helping make everyday boarding quicker and less awkward.

Rotation also allows parents to change between rear-facing and permitted forward-facing travel without removing or reinstalling the car seat.

Designed to Grow From Baby to Toddler

CYBEX GrowTech helps the Sirona S adapt as your child develops, combining an adjustable headrest, multiple recline positions and removable support layers.

The seat is suitable from 61 cm as supplied. A soft Comfort Inlay is included and can support children until approximately 85 cm. For use from birth, the separately available Sirona S-Line Newborn Inlay adds two further support layers for babies measuring 40–60 cm.

The seat structure supports a hip-healthy M-position, while the adjustable recline helps provide a more comfortable posture in both rear-facing and forward-facing positions. Sirona S has also received the AGR Seal of Approval for its ergonomic design and functionality.

Linear Side-Impact Protection

The CYBEX Sirona S combines an energy-absorbing shell, protective headrest and integrated Linear Side-impact Protection system.

The L.S.P. element can be extended on the side nearest the vehicle door. In a side collision, it is designed to begin managing the impact before directing forces into the seat’s energy-absorbing shell and headrest.

CYBEX states that the complete system can reduce side-impact forces by up to 25% compared with the same seat without its L.S.P. system, based on the company’s internal testing.

CYBEX Base S Installation

Sirona S must be installed using the separately available CYBEX Base S. The base connects to compatible vehicles through ISOFIX and uses a supporting load leg to provide additional stability.

Installation indicators help confirm that the ISOFIX connectors, load leg and car seat have been correctly engaged. The Sirona S then clicks on and off the base when required.

Always check the CYBEX vehicle compatibility tool before purchasing. Sirona S cannot be installed using the vehicle seat belt and is not compatible with Base T, Base Z or Base Z2.

One Base, Three S-Line Car Seats

Base S creates a modular car-seat system designed to support different stages of family travel.

Parents can begin with the CYBEX Cloud S infant carrier before moving to the rear-facing Sirona S toddler seat. Alternatively, families who prefer a forward-facing seat with an impact shield and integrated airbag can choose the Anoris S Airbag.

The Base S is compatible with:

• CYBEX Cloud S
• CYBEX Sirona S
• CYBEX Anoris S Airbag

This gives families a choice of two different toddler-seat routes while continuing to use the same ISOFIX base.

Comfort and Style Fabrics

The CYBEX Sirona S is available in Comfort and Style finishes.

Comfort models combine soft upholstery with a ventilated seat shell designed to encourage airflow around the child. Style models add breathable 3D mesh, which CYBEX states can increase airflow by up to six times compared with conventional fabrics.

Style versions also feature two-tone leather-look detailing inspired by premium vehicle interiors and include a detachable XXL sun canopy. The canopy provides UPF50+ protection, while its mesh window encourages additional ventilation. The mesh section itself is not UPF50+.

Both versions have removable fabric covers that can be machine washed at 30°C in accordance with the product instructions.

CYBEX Sirona S vs Sirona T

The CYBEX Sirona S replaces Sirona T within the new Platinum S-Line modular system.

Both seats offer extended rear-facing travel, 360-degree rotation, adjustable recline and Linear Side-impact Protection. Sirona S builds on that formula with a higher maximum child weight, a longer approximate usage period, updated approval and a more flexible modular base.

The principal improvements include:

• A maximum child weight of 20 kg rather than 18 kg
• Approximate use to 4.5 years rather than four years
• Updated UN R129/04 approval
• CYBEX GrowTech with adaptable support layers
• From-birth use from 40 cm with the optional newborn inlay
• New Comfort and Style fabric choices
• Base S compatibility across Cloud S, Sirona S and Anoris S Airbag

There is an important compatibility difference. Sirona T works with Base T and selected earlier bases, whereas Sirona S requires the new Base S. Sirona S is not compatible with Base T.

Sirona T remains an established seat with an independent ADAC “Good” result. Sirona S is the more future-facing choice for families beginning a new CYBEX modular system, particularly those who want the higher 20 kg limit and the flexibility offered by Base S.

Chelsea Baby’s View

The CYBEX Sirona S is a meaningful progression from Sirona T, particularly for families who want to keep their child rear-facing beyond the typical four-year point.

Its increased 20 kg weight limit may allow some children to remain within the seat for longer, while the one-handed rotation, magnetic belt holders and Easy-In crotch pad make a noticeable difference during everyday use. The optional newborn support also gives parents greater flexibility, although many families may prefer to begin with Cloud S before moving onto Sirona S.

The Base S system is one of its strongest advantages. Parents can start with Cloud S and then choose between the extended rear-facing Sirona S or forward-facing Anoris S Airbag without purchasing another base.

Suitability will still depend on your child, vehicle and chosen seating position. We recommend checking compatibility and arranging a demonstration before purchasing wherever possible.