Rear-Facing Safety, Reimagined for Real Life

From those precious early months to the busy, bustling toddler years, your child deserves a car seat that rises to every occasion. The CYBEX Sirona G3 i-size Plus in Stone Grey is a masterclass in thoughtful engineering — blending industry-leading safety with the kind of everyday ease that makes family life that little bit smoother. Whether you're navigating the morning school run or setting off on a longer adventure, the Sirona G3 is the seat that quietly does everything right.

A Safer Way to Travel — From Birth to Four Years

Up to 50% Higher Safety Levels in Rear-Facing Position

The Sirona G3 is built around a simple but powerful principle: rear-facing is safer. Independently tested to deliver up to 50% higher safety levels compared to the same seat used forward-facing, it keeps your child in the optimal protective position for as long as possible — which, in line with current guidance, should be until at least 15 months old.

In the event of a frontal collision, the seat's padded shell absorbs and distributes impact forces whilst holding your child securely, significantly limiting movement and reducing strain on their neck. It's the kind of protection that gives you genuine confidence, every single journey.

Suitable From Birth to Approximately Four Years

With a double newborn inlay accessory (sold separately), the Sirona G3 can welcome babies from as small as 40 cm, supporting children all the way up to 105 cm and a maximum of 19 kg. That's an impressive span of use — from the tiniest newborn to a thriving four-year-old — making this a car seat that truly earns its keep over time.

Designed Around the Way You Actually Parent

360° Rotation for Effortless Boarding

One of the Sirona G3's most celebrated features is its smooth 360° rotation system. Swing the seat towards the car door, settle your child comfortably into position, and rotate it back — all without the back strain and awkward angles that make standard car seat installation such a chore. Whether your child is wide awake and wriggling or sound asleep after a long day, getting them in and out has never felt this straightforward.

Five Recline Positions for Every Stage

As your child grows, their comfort needs change — and the Sirona G3 adapts accordingly. With five individual recline settings across both rear and forward-facing positions, you can always find the perfect angle for travel, whether that's a fully reclined nap position on a long journey or a more upright setting for shorter trips. Every position has been ergonomically designed to keep your child comfortable and correctly supported.

Advanced Protection That Opens Automatically

25% More Side-Impact Protection

The Sirona G3 is fitted with CYBEX's advanced Linear Side-Impact Protection (L.S.P.) System, combined with an energy-absorbing shell and a specially designed headrest, delivering 25% more protection in a side collision compared to seats without the system. Impressively, the L.S.P. panel opens automatically the moment the seat is removed from the box — and folds neatly away when space is at a premium.

ISOFIX & Load Leg for Rock-Solid Stability

Secure installation is non-negotiable, and the Sirona G3 delivers on that front with user-friendly ISOFIX connectors and a dedicated load leg that prevents forward rotation in the event of an accident. Together, they create a foundation that feels reassuringly solid every time you click it into place.

Part of the CYBEX G3 Modular Family

The Sirona G3 is fully compatible with both the Base G3 and Base G, meaning that if you already own one of these bases from your infant car seat days, the Sirona G3 simply clicks straight in — no additional base purchase required. It's a seamlessly joined-up system that rewards families who plan ahead, saving both time and money as your child grows.

Key Features

• Up to 50% higher safety in rear-facing position — independently tested and verified
• 360° rotation — effortless, back-friendly boarding and off-boarding
• L.S.P. System — 25% more side-impact protection, opens automatically
• Five recline positions — rear and forward-facing comfort at every stage
• Suitable from birth to approx. 4 years — 40 cm to 105 cm / up to 19 kg
• Double newborn inlay accessory — supports from 40 cm (sold separately)
• M-position leg support — promotes healthy hip and spine development
• Belt holders included — keeps harness straps tidy and easy to use
• ISOFIX & load leg — secure, stable installation every time
• Compatible with Base G3 & Base G — part of the G3 Modular System
• UN R129/04 i-Size certified — meets the latest European safety standards
• Product weight: 6 kg (13 kg with Base G3)