Diono Radian 3RXT
The Diono Radian 3RXT rear-faces up to 50 lb, forward-faces up to 65 lb, and is 17 in wide, per Diono. A slim steel-frame seat that folds and goes rear-facing to 50 lb, forward-facing to 65 lb and then to a high-back booster.
DiscontinuedNo longer made or sold new. Specs are kept for comparing generations.
- $299.99List price
- 50 lbRear-facing to
- 65 lbHarness to
- 120 lbBooster to
Radian 3RXT: key facts
- The Diono Radian 3RXT rear-faces from 5 to 50 lb and 18 to 44 in tall; forward-faces with a harness from 22 to 65 lb and 30 to 57 in tall; works as a booster from 40 to 120 lb and 40 to 57 in tall, per Diono.
- Outgrown by height: "Rear-facing: Top of head must be 1.5 in (3.8 cm) below the top of the car seat shell. Forward-facing: Top of child's ears MUST be below top of car seat shell."
- It installs with LATCH or seat belt.
- Diono says it expires 10 years after the date of manufacture.
- Diono lists it as certified for aircraft ("This child restraint is certified for use in aircraft only when in harness mode. This child restraint is not certified for use in aircraft when used in booster mode.").
- It's 17 in wide at the widest point and weighs 30.6 lb.
From Diono's manual and published specs. Always follow the limits on your seat's labels.
How the Radian 3RXT stacks up
Against the 58 all-in-one car seats we track. The shaded band is where the middle half of them fall; the dot is this one.
The same as most all-in-one car seats (10 years).
Above the 40 lb most all-in-one car seats list.
Below the typical range for all-in-one car seats (18 in to 19.5 in).
Above the typical range for all-in-one car seats (20 lb to 29.3 lb).
Within the typical range for all-in-one car seats ($229.99 to $399.99).
Flying with the Radian 3RXT
Diono's label: “This child restraint is certified for use in aircraft only when in harness mode. This child restraint is not certified for use in aircraft when used in booster mode.” It is 17 in wide at its widest point.
What airlines say about car seats:
- American: “Each ticketed customer is allowed 1 stroller and 1 car seat to be checked free of charge” “If an unoccupied, adjoining seat is not available, the gate agent will check the safety seat to your final destination.” Source
- Alaska: “We will transport your child's car seat and stroller free of charge as checked baggage.” Source
- JetBlue: “Checking a child safety seat will not count towards your checked baggage allowance and there is no fee assessed” Source
- Spirit: “One (1) car seat will be accepted per child as checked baggage at no charge.” Source
- Frontier: “strollers and car seats can be checked for free.” Source
- Allegiant: “There is no charge for checking or gate checking one car seat per fare-paying passenger.” Source
- Breeze: “Child seats may be carried on board the aircraft if a seat has been purchased for the Infant or Child” Source
Quoted from each airline's page as of 2026-11-02.
Listed features
- Folds for travel
- Approved for aircraft use in harness mode
- Includes steel anti-rebound bar
Worth checking
- Heavy at 30.6 lb
- Needs 30-36 in of front-to-back room rear-facing
- Fabrics contain flame retardants (not legally restricted types)
Where to buy the Radian 3RXT
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- Discontinued. You may still find it used or on clearance.
- Check for recalls: Search the agency's recall list with the model number and date code from the label: NHTSA recall search.
- Car seat use and installation: see NHTSA's car seat page, which also lists free car seat inspection by certified technicians. Check the label and the maker's instructions, and ask your pediatrician about your child.
Full specs
| Diono Radian 3RXT | |
|---|---|
| Type | All-in-one |
| List price | $299.99 |
| Rear-facing weight | 5–50 lb |
| Rear-facing height | 18–44 in |
| Forward-facing weight | 22–65 lb |
| Forward-facing height | 30–57 in |
| Booster weight | 40–120 lb |
| Booster height | 40–57 in |
| Seat weight | 30.6 lb |
| Width | 17 in |
| Head rule | Rear-facing: Top of head must be 1.5 in (3.8 cm) below the top of the car seat shell. Forward-facing: Top of child's ears MUST be below top of car seat shell. |
| Newborn insert | Infant head and body support cushion; infant use 5-22 lb (2.3-10 kg) per recline level indicator |
| Installation | LATCH, seat belt |
| Load leg | No |
| Anti-rebound bar | Yes |
| Rotates | No |
| Aircraft label | Certified for aircraft, per the maker |
| No added flame retardants | No |
| Expires after | 10 years |
Compare the Radian 3RXT with
How each closest rival differs from the Radian 3RXT, from the makers' specs.
- CybexEternis Srear-facing to 50 lbforward-facing to 65 lb$299.95
- 2.8 in wider
- 4.6 lb lighter
- $0 less
- EvenfloSymphony Extend Breeze 3-in-1rear-facing to 50 lbforward-facing to 65 lb$279.99
- 1.5 in wider
- 13.6 lb lighter
- $20 less
- GracoExtend2Fit 3-in-1rear-facing to 50 lbforward-facing to 65 lb$269.99
- 2 in wider
- 10 lb lighter
- $30 less
- DionoRadian 3R SafePlusrear-facing to 50 lbforward-facing to 65 lb$259.99
- 1.3 lb lighter
- $40 less
Radian 3RXT: questions answered
From Diono's published specs, last checked 2026-11-06.
Does the Diono Radian 3RXT rear-face longer than other all-in-one seats?
Yes. Its 50 lb rear-facing limit is the highest of the 70 all-in-one seats we track, tied with 14.
Will the Diono Radian 3RXT fit three across or in a small car?
It's narrower than 86% of the all-in-one seats we track, at 17 in. The narrowest is the Chicco Fit3x ClearTex Ultra-Slim All-in-One at 16.7 in. Fit depends on your vehicle; check each seat's manual and your vehicle manual. Car seat use and installation: see NHTSA's car seat page, which also lists free car seat inspection by certified technicians. Check the label and the maker's instructions, and ask your pediatrician about your child.
Can you bring the Diono Radian 3RXT on a plane?
Yes, Diono lists it as certified for aircraft; look for the red-lettered label that says so. The FAA asks that a car seat go in a window seat so it doesn't block the aisle, and the crew will look for that label. It weighs 30.6 lb to carry through the airport.
Radian 3RXT or Eternis S: what's different?
By the makers' specs, the Eternis S lists for $0.04 less. See every spec side by side.
Is it OK to buy a used Radian 3RXT?
NHTSA publishes guidance on used car seats on its car seat page. Diono lists a lifespan of 10 years from manufacture for this model. Check the label and the maker's instructions, and ask your pediatrician about your child.
Still wondering? Write to us at hello@cribpicks.com and we'll look it up.
More all-in-one car seats
- GracoSlimFit3 LXrear-facing to 40 lbforward-facing to 65 lb$299.99
- Graco4Ever DLX 4-in-1rear-facing to 40 lbforward-facing to 65 lb$319.99
- DionoRadian 3QXrear-facing to 50 lbforward-facing to 65 lb$399.99
- ChiccoOneFit ClearTexrear-facing to 40 lbforward-facing to 65 lb$329.99
- Maxi-CosiPria All-in-Onerear-facing to 40 lbforward-facing to 65 lb$269.99
- Maxi-CosiPria Maxrear-facing to 40 lbforward-facing to 65 lb$329.99
Where these specs come from
Last checked 2026-11-06. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.