Marathon ClickTight › fit in › Kia Rio

Will the Britax Marathon ClickTight fit in a 2018–2023 Kia Rio?

Yes — the Britax Marathon ClickTight fits a 2018–2023 Kia Rio, with a caveat.
The Marathon ClickTight is about 18.5" wide; the Rio's usable rear bench is about 47". It fits one rear position comfortably. Three across is tight (55.5" needed vs 47"). Note: rear legroom here is limited, so a rear-facing install may crowd the front passenger.

18.5"Marathon ClickTight width

47"Rio rear bench

Tightthree across

★★★★☆NHTSA Ease-of-Use

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What fits this Rio

One seat, rear position: Yes. The Marathon ClickTight installs in an outboard rear position of a 2018–2023 Kia Rio, though you may slide the front seat forward for rear-facing.
Three across: Tight — three need ~55.5" against only ~47". A narrower seat is the better bet.
Modes this seat covers: rear-facing → forward-facing.
LATCH: lower anchors up to 40 lb; the Rio 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 Marathon ClickTight's width (Britax published spec (~18.5 in)) and the Rio's rear-bench width (Typical for subcompact car — approximate, verify install in your vehicle) are both approximate — confirm with a test-fit before buying.

Common questions

Will the Britax Marathon ClickTight fit in a 2018–2023 Kia Rio?

Yes — the Britax Marathon ClickTight (18.5" wide) fits a single rear seating position in a 2018–2023 Kia Rio. Because this vehicle has limited rear legroom, a rear-facing install may require sliding the front seat forward. Three across is tight — its rear bench is about 47" and three of these would need 55.5".

Can you fit three Marathon ClickTights across a Rio?

Probably not — three Marathon ClickTights need about 55.5" but the Rio's usable bench is only about 47". Consider a narrower seat — see our narrowest-seats guide.

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.