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Overview

The Diono Radian 3R 3-in-1 convertible car seat is built to grow with your child from birth to booster, offering up to 10 years of use in one slim, space-saving design. With extended rear-facing capability, reinforced steel core construction, and a narrow 3-across fit in most vehicles, it’s designed for families who want long-term safety, everyday comfort, and a practical solution for busy back seats.

Diono Radian 3R, 3-in-1 Convertible Car Seat, Rear Facing & Forward Facing, 10 Years 1 Car Seat, Slim Fit 3 Across, Jet Black

Model: 54020
Web Code: 14495550
30+ have looked at this recently
Sold and shipped by | 3.2 seller rating (15 reviews)

Sale ends: *

Colour: Black Jet

Available for deliveryAvailable online only

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Seller Return Policy

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Warranty

Check with the manufacturer for details.

For Quebec residents: See the Availability Guarantee disclosure in the Specifications section below.

What's included:

  • 1. LATCH/UAS Storage2. Top Tether3. SafeStop™4. Instruction Manual Storage5. Harness Straps 6. Harness Strap Hook7. Forward-Facing Belt Path8. Chest Clip9. Radian 3R Harness Pads10. Buckle11. Buckle Pad12. Harness Release13. Harness Adjuster Strap14. Expandable Side Wings15. Rear-Facing Belt Path16. Upper Booster Belt Guides17. Booster Belt Guide18. Detachable Rear-Facing Base19. Lap Belt Cushion U.S. Only20. 80/20 Overhang Guidance

10 years of use in one slim convertible car seat

The Diono Radian 3R 3-in-1 convertible car seat is designed to support your child from birth through the booster years, giving families one dependable seat for everyday drives, carpools, and longer road trips. With a slim profile that can fit 3-across in most vehicles, extended rear-facing use, and a reinforced steel core, it delivers long-lasting value without giving up comfort or space.

10 Years 1 Car Seat for growing families

Designed to grow with your child from birth to booster, the Radian 3R offers long-term use in one seat so parents can invest once and stay ready for every stage ahead.

Rear-facing for longer

Supports rear-facing use up to 50 lb, helping families keep little ones in the rear-facing position longer as recommended for the early years.

Slim fit design that helps fit 3-across

The signature Diono slim profile is made for busy back seats and growing families, helping fit 3 car seats across in most vehicles without taking up unnecessary space.

Steel core construction for dependable protection

Built with a mechanically engineered reinforced steel core made from automotive-grade high-strength steel to help shield and support your child on every journey.

Comfort for everyday rides and longer road trips

The deep, supportive seat design helps create a comfortable ride for growing children, whether you’re heading across town or spending more time on the road.

Easy-remove, machine washable cover

Real family life gets messy. The removable cover is designed for easier cleanup, so you can keep the seat fresh after everyday spills, crumbs, and snack-time accidents.

A practical choice for multi-child households

The narrow profile makes the Radian 3R especially useful for families managing multiple children, smaller back rows, or a 3-across seating setup.

Designed for everyday family travel

From school drop-offs to weekend visits and longer drives, the Radian 3R combines extended use, a compact footprint, and dependable construction in one versatile convertible car seat.

Use range

Rear-facing: 5–50 lb (2.3–22.7 kg)

Forward-facing: 26.5–65 lb (12–29.5 kg)

Booster mode: 40–120 lb (18–54 kg)

Maximum child height: up to 57 in (144.8 cm)

For Quebec residents – Disclosure under the Consumer Protection Act

In compliance with Bill 29, Best Buy and third-party sellers on Best Buy Marketplace do not guarantee the availability of replacement parts, repair services, or maintenance information for any products. Coverage provided through any Best Buy Protection programs and applicable manufacturer warranties, if any, remain in place. Please contact the manufacturer directly for information about their availability guarantee.

Shipping Charges

Free standard shipping may be available on orders over a minimum amount (before taxes, fees, and promo codes). Shipping charges may vary based on item size and your shipping address. Want a shipping charge estimate? Simply add an item to your cart, then access the cart and enter your postal code in the shipping estimate section.

Processing Time

Most items ship within 2 business days after an order is placed*. Allow additional time for shipping to your address.
*Please note: If an item you ordered becomes unavailable, you'll be notified and a full refund will be processed within 2 business days.

Shipping Area Restrictions

Shipping is not available in the following areas*:
  • Quebec (Local)
*Please note: Shipping area restrictions may vary for large items. If an item can't be shipped to your address, we'll let you know during the checkout process.
Product Category
Car seats
Return/Exchange Period
30 days
Condition
Unopened

To protect the safety of our customers; this product cannot be returned if opened

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