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	–	–

Diono Radian 3RXT

5–120 lb

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Maxi-Cosi Pria Max

4–100 lb

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As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Weight ranges are the manufacturer's published limits across all modes.

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

Diono Radian 3RXT

See price on Amazon

Maxi-Cosi Pria Max

See 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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