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Diono Radian 3RXT Review: All-in-One Convertible Car Seat

diono radian rxt

If you’re shopping around for a great convertible car seat that can grow with your child all the way from a newborn to finally outgrowing a booster seat, the Diono Radian 3RXT is one of the best car seats money can buy. Learn more in our Diono Radian 3RXT review.

Diono Radian 3RXT Review: At A Glance

Of course, the first things you want to consider when buying a car seat is safety and weight limits.

Safety features

The Diono Radian 3RXT is one of the safest convertible car seats out there. One of the most important safety features in a car seat is protection from side impacts.

The entire car seat is fitted with high quality EPS foam that serves as an excellent shock absorption medium to protect your child from all sides.

It is very solidly built and is actually incredibly heavy. This is a plus point for the car seat, as heavier seats tend to be more sturdy. There’s also a signature SuperLatch system that keeps the seat very securely attached to the car.

It will hardly move once you’ve installed it!

It’s made with a sturdy steel frame and the sides of the seat are reinforced with aluminum.

Side note: due to the weight, you may actually find it quite cumbersome to move it from one car to another, so portability is definitely not one of this car seat’s strong suits!

You can also use this car seat for air travel, as it is FAA approved if you use the 5 point harness. You can’t use it in booster mode on an airplane, and really, you don’t need to, either.

Just because the Radian 3RXT is built like a tank does not mean it’s not comfortable! There is plenty of head support and the 5-point harness will hold your child rather snugly into the seat.

The harness works in both front facing and rear facing modes.


The Radian 3RXT is actually quite a slim car seat as you can get away with installing 3 car seats next to one another in the back seat of a medium sized vehicle.

You don’t even need 3 Radians, as the Radian is slim enough to fit between two other car seats too.

The outer covering of the 3RXT is very comfortable and elegant with modern trims and straight lines. The base of the seat is made from memory foam to fit your child’s contour and provide comfort.

Car seat covers always get dirty, so you’ll be happy to know that it’s very easily removable and you can toss it in the washing machine for easy cleaning.

Keep in mind that you must air dry the cover, as it will spoil in the dryer.

Weight and height limits

The Diono Radian 3RXT is suitable for newborns weighing 5 pounds and up.

Rear facing mode

Weight: 5-45 pounds

Height: 44 inches

Front facing mode

Weight: 20-65 pounds

Height: 57 inches

Booster mode

Weight: 50-125 pounds

Height: Shoulders should come up to 4th strap

Who is the Diono Radian 3RXT good for?

The Diono Radian is a very versatile (if not pricey) car seat that is well suited for any growing family. Aside from the robust safety and comfort features, the Radian is incredibly slim at just 17 inches across. This lets you fit up to three car seats in the back of a mid-size car.

The Diono Radian 3RXT is a modern car seat designed for modern cars, which tend to be a little narrower and smaller.

What’s more, since the Radian 3RXT is a convertible car seat, it can grow with your child right from a newborn all the way to a preteen.

It’s pretty much a one-time investment that will last you a long time. The car seat has a manufacturer’s expiry date of 10 years from the year of manufacture, so if you’re sticking to the expiry date, you could buy the car seat right when your child is born and use it all the way till they pretty much outgrow it.

safety rating


The Diono Radian 3RXT is very easy to install securely into your car. To start, you’ll need to install the rear-facing attachment which balances the car seat in the rear-facing position.

You can then pass the seatbelt through the bottom of the car seat and buckle it in.

If your car has the latch system, you can use the latches to secure the car seat into place and pull on the strap to tighten it securely.

It’s important that the car seat moves less than an inch left to right once it has been installed.

Installing forward facing is also quite straightforward. You need to pull out the adjustable bottom to get it to balance in front facing mode first.

Then grab the tether, run it over the back of the seat and attach it to the tether behind the seat. If your car does not have this, you can just pass the seat belt through the slot and secure it.

You can also use the latch system if your car has it.

Diono Radian Feature Recap

  • Rear-facing, front-facing, and booster modes
  • Aluminium reinforced sides and a full steel frame offer top safety ratings
  • Diono Radian 3RXT rear facing comfortably seats infants weighing in at 5-45 pounds, while in combination with a 5 point harness it can seat children weighing in at between 20-80 pounds, it then becomes a booster for children over 120 pounds.
  • Installation is enhanced through the proprietary SuperLATCH system.
  • FAA certified 3 seat can easily fit in the backseat in medium sized cars in addition to being able to fold flat for travel.
  • Crash tested by NCAP which is the industry standard for car seat safety and performance during crash situations.


  • All-steel frame which means it is one of the most safe convertible car seats in the market
  • Memory foam and infant body support cushions for enhanced child comfort in travel
  • Adjustable headrest with reinforced walls makes for a sturdy and robust construction.
  • Very slim and can easily fit next to other car seats in your vehicle
  • Energy absorbing harness and EPS foam offer enhanced comfort and safety.
  • The Diono Radian is built to last for up to 10 years and thus it the most durable of the best infant car seats.
  • It makes use of the LATCH system and rubber bottom grips which makes installation super easy.
  • Comes with an additional set of harness intended for use when the child weighs more than 65 pounds.
  • The Diono Radian RXT booster has a low seating profile and expandable  sides which makes it easy for the child to climb into the vehicle and offers extra leg support.
  • The radian car seat Comes with a Safestop harness that is energy absorbent.
  • Its adjustable setting including rear tether, adjustable headrest, three buckle, and five shoulder positions offer utmost safety and comfort on the road.
  • Comes with an angled cup holder ensuring minimal spillage.
diono radian rxt review
diono steel frame


  • Very heavy, not easy to carry
  • Some people feel upper latch straps are not as secure as other car seats
  • Must rethread straps to change height
  • Just one recline angle

The Verdict

diono radian rxt

The Diono Radian 3RXT Convertible car seat is definitely one of the top car seats out there despite its cons. While a minority of parents have complained about its bulk and weight, I do believe that its robust construction including a steel frame and one of the safest and comfortable side impact protection more than make up for this flaw.

Nevertheless I do believe this is a matter of personal preference for any parent. The diono cup holder can be made more secure through DIY methods if proper installation is made. It has a one year warranty though for a car that is built to last for 10 years I doubt that you would ever need to call in the warranty.

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