Radian 3QXT › fit in › Mazda CX-9
Will the Diono Radian 3QXT fit in a 2016–2023 Mazda CX-9?
Yes — the Diono Radian 3QXT fits a 2016–2023 Mazda CX-9.
The Radian 3QXT is about 17" wide; the CX-9's usable rear bench is about 53". It fits one rear position comfortably. Three even fit across the back (51" needed vs 53").
The Radian 3QXT is about 17" wide; the CX-9's usable rear bench is about 53". It fits one rear position comfortably. Three even fit across the back (51" needed vs 53").
17"Radian 3QXT width
53"CX-9 rear bench
Yesthree across
★★★☆☆NHTSA Ease-of-Use
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What fits this CX-9
- One seat, rear position: Yes. The Radian 3QXT installs in an outboard rear position of a 2016–2023 Mazda CX-9 with room to spare.
- Three across: Yes — three need ~51" against a ~53" bench. Test-fit; three-across is decided by half-inches.
- Modes this seat covers: rear-facing → forward-facing → booster.
- LATCH: lower anchors up to 40 lb; the CX-9 has 2 lower-anchor positions.
ℹ️ Informational only — built from NHTSA public car-seat ratings and published seat/vehicle dimensions. This is not a safety certification and not a substitute for the seat and vehicle manuals. Always confirm the fit and install yourself before every trip. The Radian 3QXT's width (Diono published spec (17 in)) and the CX-9's rear-bench width (Typical for 3-row suv — approximate, verify install in your vehicle) are both approximate — confirm with a test-fit before buying.
Common questions
Will the Diono Radian 3QXT fit in a 2016–2023 Mazda CX-9?
Yes — the Diono Radian 3QXT (17" wide) fits a single rear seating position in a 2016–2023 Mazda CX-9. Three of them also fit across its roughly 53" rear bench.
Can you fit three Radian 3QXTs across a CX-9?
Yes — three Radian 3QXTs need about 51" and the CX-9's usable bench is about 53". It's close, so test-fit before buying.
Sources: seat ratings & modes — NHTSA (pulled 2026-06-18); dimensions — manufacturer specs and owner measurements. Informational only — built from NHTSA public car-seat ratings and published seat/vehicle dimensions. This is not a safety certification and not a substitute for the seat and vehicle manuals. Always confirm the fit and install yourself before every trip.