Diono Radian 3RXT vs Maxi-Cosi Pria Max

Both are convertible car seats — here are their published manufacturer specs side by side.

This compares published manufacturer specs — not safety or fit advice. The seat's manual, your vehicle's manual, NHTSA's tools and a certified CPST are the fit-and-safety authority; always check them before installing.

Spec	Diono Radian 3RXT	Maxi-Cosi Pria Max
Stage	Convertible	Convertible
Narrow (3-across)	✓	–
Extended rear-facing	✓	–
FAA-approved	✓	✓
Lightweight / travel	–	–

How they differ

the Diono Radian 3RXT is listed narrow (roughly ≤17″) for fitting three across a back seat; the Maxi-Cosi Pria Max isn't listed narrow
the Diono Radian 3RXT lists extended rear-facing (a higher rear-facing weight limit, ~40-50 lb); the Maxi-Cosi Pria Max doesn't

Published limits

Mode	Diono Radian 3RXT	Maxi-Cosi Pria Max
Rear-facing	5–50 lb · 18–44 in	4–40 lb · 19–40 in
Forward-facing harness	22–65 lb · 30–57 in	22–65 lb · 29–49 in
Booster (with back)	40–120 lb · 40–57 in	40–100 lb · 43–52 in
Useful life	10 yrs from purchase	10 yrs from manufacture

Diono Radian 3RXT: All-in-one (rear-facing → forward-facing harness → high-back booster; no backless mode found in manual). Forward-facing also requires at least 1 year old + 22 lb minimum (printed manual requirement). No separate age requirement printed for booster mode. Expired over 10 years from date of PURCHASE (manual's own wording — most other brands print "manufacture").

Maxi-Cosi Pria Max: 3-in-1 all-in-one (rear-facing → forward-facing harness → high-back belt-positioning booster; no backless mode found in manual — the site currently lists this model's stage as "convertible" only, but the manual confirms a booster mode too). Forward-facing requires at least 1 year old.

Printed verbatim in the manufacturer's manual (Diono Radian 3RXT Car Seat Instruction Manual · Maxi-Cosi Pria Max 3-in-1 (Item CC208) US Owner's Manual); “—” = not published for that mode, “not yet sourced” = we haven't read that manual yet, not that the seat has no limit. How we source these →

Recall record

Diono — 2 on NHTSA's record · Maxi-Cosi — 6 on NHTSA's record.

That is the record of the brand — not a verdict on these models. A recall names specific models and manufacture-date ranges, and a seat missing from the record is not "recall-free": check nhtsa.gov/recalls with the model and date of manufacture on your seat's label. Source: NHTSA, retrieved 2026-09-05.

Where to buy

Check the Diono Radian 3RXT price on Amazon →

Check the Maxi-Cosi Pria Max price on Amazon →

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FAQ

What's the difference between the Diono Radian 3RXT and the Maxi-Cosi Pria Max?
The Diono Radian 3RXT is narrow for 3-across, extended rear-facing, FAA-approved for aircraft; the Maxi-Cosi Pria Max is FAA-approved for aircraft. Both are convertible car seats.

Which fits three across, the Diono Radian 3RXT or the Maxi-Cosi Pria Max?
The Diono Radian 3RXT is listed narrow (~≤17″) for 3-across; the Maxi-Cosi Pria Max isn't. Three-across fit still depends on your exact vehicle — confirm before buying.

Which is right for my car and child, the Diono Radian 3RXT or the Maxi-Cosi Pria Max?
That depends on your specific vehicle and child — this page compares published manufacturer specs only, not fit or safety. Check the seat manual, your vehicle manual, NHTSA's car-seat finder and ideally a certified CPST before deciding.

Citing these specs? Go ahead — published manufacturer data, last verified 2026-06-11. Copy a ready-made reference:

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