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Diono Radian 3RX Latch 3-Across All-in-One Convertible Car Seat

$ 269.99 USD

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The original All-in-One convertible car seat designed to fit 3 across and with our famous steel core inside for optimum safety. Now rear facing for even longer (up to 50 lb / 22.7 kg) and featuring all new head support infant insert, expect 10 years of safety from just one car seat.

  • NEW rear facing for longer - now up to 50 lb / 22.7 kg
  • NEW head support infant insert for cushioned comfort
  • NEW easy remove covers for easy cleaning - machine wash and dry.
  • NEW Instruction booklet to improve the user experience and using industry best practice.
  • NEW easy to follow labelling on the fabric seat covers to improve and simplify installation for the user of the car seat.
  • NEW and improved car seat fabrics

10 YEARS - 1 CAR SEAT Built from high quality materials and versatile design for growing children, the Radian 3 provides 10 years of service.

THE ORIGINAL 3 ACROSS Radian 3RX features a slimline, space saving design at only 17” wide, that allows you to install three across in most vehicles.

DIONO STEEL CORE Engineered with the famous Diono full steel core for safety you can feel. This high-strength core has inherent integrity and forms an unyielding structure to shield and protect your little one.

REAR-FACING FOR EVEN LONGER With extended rear-facing from birth up to 50lb / 22.7 kg to keep your child in the safest travel position for as long as possible.

SOLID SIDE IMPACT PROTECTION Aluminium reinforced sides and thick energy absorbing foam distributes crash forces.

HEAD SUPPORT INFANT INSERT The removable head support infant insert features padded support for cocooned comfort. Then as your infant grows simply remove.

EASY REMOVE COVERS Radian 3RX features easy remove covers. So when the next journey gets messy, easily remove to machine wash.

TRAVEL READY Radian car seats are super portable and fold flat for easy travel. They are also FAA Approved and certified for use on aircraft!

SUPERLATCH INSTALLATION Our SuperLATCH system makes installation easy and super secure. An audible click lets you know when connectors are locked in safe.



  • Aluminum reinforced sides lined with foam.
  • Folds for easy transportation and storage.
  • Aircraft Certified (FAA Approved)
  • New head support infant insert for cushioned comfort
  • New Anti-slip XL comfort harness pads
  • 5 point harnessExpandable sides and longer 
  • seat bottom for leg support and comfort.
  • Low sitting profile makes it easy for your child to climb in and out of their seat as they grow.
  • Reinforced steel core, made from automotive grade, high strength steel to protect and shield.
  • Energy absorbing EPS foam panels on all sides and even under their bottoms.
  • Rear-facing and forward-facing top tether capability.
  • Five shoulder and three buckle positions for custom fit.
  • Bright new cover designs are more comfortable with soft hard wearing fabrics.
  • SuperLATCH connectors with audible click installation.
  • Storage pocket for SuperLATCH, Top Tether and Safe Stop.
  • New easy remove cover, for quick machine wash and dry.
  • Memory foam padding for superior comfort and support.
  • Rubber bottom grips for no-slip installation.
  • Cup holder included (option to purchase additional)

Seat Weight

26.4lb / 11.97 kg

Overall seat dimensions (lowest position inches)

H 28.5” x W 17” x D 16”

Overall seat dimensions (lowest position cm)

H 72.4cm x W 44cm x D 41cm

Seat Folded Dimmensions (inches)

H 28.5” x W 17” x D 7”

Seat Folded Dimmensions (cm)

H 72.4cm x W 44cm x D 17.8cm

Vehicle seat bite to front FF length

17” / 44cm

Inside shoulder width

12” / 31cm

Inside hip width

12” / 31cm

Inside seat depth

13” / 33cm

Rear facing installation depth

30”/ 76.2cm

Inside seat height
(base to accommodating)

26” / 67cm

External widest point

17” / 44cm

We are happy to accept returns on unused, unaltered merchandise in its original packaging and with all original tags. Return requests must be made within 7 days from the original date of purchase for a refund (less any shipping fees) and within 30 days for store credit or exchange. All returns must be pre-authorized by a Tadpole staff member, either in person, or by phone or email if you are mailing the merchandise back. Damaged packaging will be subject to a 10% restocking fee. All unaltered merchandise could also be subject to a restocking fee anywhere between 10-25% depending on the value of the original merchandise and the reason for return. Once we have received your return we will process the refund/store credit/exchange within 2 business days. Store credit expires after 6 months. 

The following items are final sale i.e. NON-REFUNDABLE:

  • All special orders and sale items; all toy special orders are final sale; all furniture sales are final sale; damaged, defective, or missing furniture pieces will be replaced.
  • All stroller and car seats sales are final; damaged merchandise will be covered under the manufacturer's warranty.
  • All opened breastfeeding products, opened feeding products, body products are final sale.
  • All pantry items are final sale. 
  • Gift cards are non-refundable. 
  • Gifts can only be exchanged or offered store credit if returned within 30 days of the original date of purchase. 

Please note:

Orders that qualify for free shipping may be subject to a restocking fee.

If an item is damaged once opened, or during shipping, please notify us immediately. We will gladly accept returns of defective merchandise within 7 days of purchase/receipt of goods. Returned items are your responsibility until they reach the return address. Please ensure your package is returned securely to prevent any damage to the item or its packaging. Tracking is highly recommended. Any returns that are damaged when we receive them will not be refunded. We are not responsible for any items that are returned to us in error. 

Credit card orders will receive refunds in the form of a credit to the card. Please allow at least one billing cycle for credit to appear on your statement.

To request a return via email, send an e-mail to with your name, address, invoice number, item you are returning, and why you are returning it. 

Important: Please note that we do not refund delivery fees or original shipping charges.

Please send returns to:
Attn: Returns
58 Clarendon Street
Boston, MA 02116