Diono Radian® 3 RX Convertible+Booster Car Seat

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Unmatched safety. All-in-one simplicity.

Your child’s security is of top priority. Diono engineered the Radian® 3 RX with premium, innovative features like a steel alloy frame, aluminum reinforced sidewalls, energy absorbing EPS foam and a reinforced adjustable head support to keep your little one protected and comfortable. Little details like a specifically angled cup holder help to keep your little one happy. And if you’re traveling with multiple children, the Radian 3 RX gives you the flexibility to bring everyone along on life’s journeys. 

Worth the Weight

Diono's convertible car seats are made from steel for safety you can feel. The fully integrated steel frame is wrapped in thick engineered plastic to withstand severe crash forces. Deep, aluminum reinforced sidewalls provide excellent side impact protection, while energy absorbing EPS foam surrounds your child for ultimate safety. Diono car seats are definitely worth the weight.

Extended rear-facing

The Radian® 3 RX keeps children comfortably rear-facing from 5-45 pounds for the safest possible position. Premium, plush head and body support cushions are included for newborns and infants.

Room to grow

Accommodates forward-facing children up to 65 pounds in a 5-point harness and converts to booster mode for kids 50-120 pounds. The aluminum reinforced, adjustable head support and sidewalls provide additional side impact protection.

Business Class Comfort

Inspired by the best European fashions, the Radian 3 RX has bright soft fabric covers and a memory foam seat bottom. Lined with energy absorbing foam, comfort and safety go hand in hand. A tailored infant support cushion and a cup holder are included.

Three’s not a crowd 

For safety that fits 3 across the Radian® 3 RX packs innovative safety features into a sleek and slim design that allows you to fit three across (in most mid-size vehicles). Now the whole family can travel, together.

Side Impact Protection

Your child’s safety is covered. Radian® 3 RX seats feature deep, aluminum reinforced sidewalls that extend straight forward and are lined with thick, energy absorbing foam. Diono performed rigorous side impact testing to achieve the proper size, shape and strength that best protects children from side impact forces.

SuperLATCH™ Installation

The unique SuperLATCH™ system makes installation easy and secure. An audible click and visual indicator let you know when the connectors are locked.

Safe Stop®

The patented Safe Stop® harness component is a load-limiting device that absorbs energy in a crash. This unique design offers an additional layer of protection by reducing impact to a smaller, forward-facing child.

Rear-Facing Tether

As safety experts, Diono thinks of every precaution. Rear-facing tether capability helps reduce seat rotation during an impact. This unique feature is not found on every car seat. It's built it in here for an extra layer of protection when your child is rear-facing.

  • NEW! Premium, plush interlock knit fabric
  • NEW and Improved Car seat fabric cover also covers the rear of the car seat to protect the car interior and ease installation.
  • NEW! Labeled pocket on the rear of the seat contains the SuperLATCH system and top tether as well as other accessories.
  • NEW tailored infant head and body supports
  • Full steel frame for unmatched safety
  • Seats rear-facing children comfortably from 5-45 pounds
  • Seats forward-facing children from 20-65 pounds in a 5-point harness
  • Converts to a booster for children from 50 pounds up to 120 pounds
  • Unique SuperLATCH™ system makes installation easy
  • Fits 3-across in most mid-size vehicles while providing spacious interior for child
  • Infant body support cushions and memory foam ensure seating comfort
  • Aluminum reinforced sidewalls lined with energy absorbing EPS foam for superior side impact protection
  • Safe Stop® energy absorbing harness
  • 5 shoulder and 3 buckle positions adjust for a comfortable ride
  • Rear-facing tether capability
  • Expandable sides and long seat bottom allow proper leg support
  • Low-sitting profile makes it easy for your child to board
  • Angled cup holder keeps drinks upright and within easy reach
  • Rubber bottom grips for no-slip installation
  • Folds flat for travel and is FAA certified
  • Cover is machine washable
  • 10 year life from the date of purchase


  • Usage:
    • Rear-facing: 5 - 45 lbs
    • Forward-facing: 20 - 65 lbs in a 5-point harness
    • Booster: 50 -120 lbs (and up to 57")
  • Dimensions: 28.5" H x 17" W x 16" D
  • Folded: 28.5"H x 17”W x 7"D
  • Weight: 26.4 lbs


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