Diono 4-In-1 Slim Radian 3RXT Car Seat

Last updated: September 8, 2021

This multi-configuration car seat is designed to last a full 10 years as your child grows. With a reinforced steel core, durable materials, an infant insert and 12-position headrest, this seat can easily handle years of use.

Diono 4-In-1 Slim Radian 3RXT Car Seat

We looked at the top Car Seats and dug through the reviews from some of the most popular review sites. Through this analysis, we've determined the best Car Seat you should buy.

Product Details

Key Takeaway: Get the seat that grows with your kid when you choose this long-lasting vehicle safety accessory.

In our analysis of 33 expert reviews, the Diono 4-In-1 Slim Radian 3RXT Car Seat placed 4th when we looked at the top 5 products in the category. For the full ranking, see below.

From The Manufacturer

The Diono Radian 3RXT is the original 3 across All-in-One convertible car seat, trusted by over a million parents to protect their child from birth to booster 5 – 120 lb / 2.2 kg – 54 kg.Lovingly engineered with the famous Diono Steel Core and now rear facing for even longer, expect 10 years of safety from just one car seat. The 2020 Radian 3RXT provides safe and comfortable newborn positioning thanks to the new 2-in-1 infant positioning liner with integrated newborn travel high wedge. The wedge creates a lie-flat travel position, pushing baby up to reduce head slump while helping to keep airways open. As your baby grows, simply remove the wedge to allow the 2-in-1 infant positioning liner to give extra infant comfort and toddler support. Designed and engineered with complete rear facing protection, radian 3RXT will keep now your precious cargo rear facing for even longer up to 50 lb / 22.7 kg, approx. 4 years old. Then as they transition to forward facing, the aluminum reinforced headrest can be adjusted to one of 12 positions for safety that grows with them up to 57” / 145 cm tall. Built with a mechanically engineered, reinforced steel core, made from automotive grade high strength steel, the radian is always ready to shield and protect. And when your family grows, the slim fit design will fit 3 acrosin most vehicles without compromising child safety or passenger comfort. As travel experts, Diono have naturally built in super portable features to the radian 3RXT with original fold for easy transport and storage and steel reinforced cup holders to store essential road trip drinks and snacks. The radian is also aircraft certified (FAA approved), so you can take safety with you wherever you go!

Expert Reviews

What reviewers liked

High quality fit and finish everywhere, easy adjustments, an easy to remove and machine washable cover, a great detachable cup-holder, and an easy-fold capability for transport (it's also approved for air travel). The fabric is soft and breathable, and the styling is simple and sophisticated. It's truly a very high quality, safe, reliable, durable, super narrow, and comfortable seat that accommodates not only extended rear-facing, but also a wide range of baby shapes and sizes.
Narrow width makes it easy to stack. Foldable for travel.
he Radian 3RXT has color-coded belt paths designed to ease installation, as well as an easy-adjust harness system. It’s FAA-rated for use on airplanes, and folds flat for travel. It also has high safety ratings.
Birth to 120 pounds. Fits 3 across. Steel core.
Proven safety record by the manufacturer. Highly durable steel frame. 10-year expiration. Easy SuperLATCH Installation system. Folds flat for easy storage and transport. Various colors of the cover.

What reviewers didn't like

Yes, it's expensive, coming in at about $300. And it's ridiculously heavy at 30 pounds, and we totally prefer a no-rethread harness system.
Average crash test performance. Stiff buckles.
Many parents have complained that the seat is hard to install, and the angle may not be good for smaller babies. Also, some kids may outgrow the seat early – and the seat itself is relatively heavy, at over 27 lbs.
Higher price point. Not ideal for travel. Angle adjuster may be needed; sold separately.
A bit heavy. May limit legroom for front passengers. Non-intuitive installation. Single recline angle.
View our Car Seat buying guide for in-depth advice and recommendations.

From our partners