We spent a week with a 2025 Subaru Outback Onyx XT to focus on usability: measuring real cargo capacity using standard moving boxes, evaluating the integrated roof rack for ease of use, and assessing how well the load can be secured for daily duty and long trips.
Test car: 2025 Subaru Outback Onyx XT (2.4L turbo flat-four, CVT, AWD, 260 hp/277 lb-ft) on 18-inch all-seasons. Curb weight 3,900 lb. EPA rated at 23/30 mpg (city/hwy). Our testing took place over mixed suburban and highway routes at 68–78°F with light wind.
We brought tape measures, ratchet straps, and standardized U-Haul Medium boxes (18 x 18 x 16 in; ~3.0 cu ft each) to quantify real-world carry. Measured cargo bay dimensions (seats up): floor length 41.5 in to seatbacks; width 45.3 in (43.0 in between wheel arches); height 19.5 in to the top of the cargo cover, 31.5 in to the headliner. Seats folded: max floor length 74.8 in, slight forward rise (~3°), but no major step. The cargo opening is broad (max width 48.0 in; sill height 28.7 in), and the bumper cover is flat enough to slide heavy boxes without gouging paint.
Standard-box loading results: with the rear seats up and cover retracted, we fit 6 Medium boxes to the window line and 8 to the headliner without impinging the hatch latch; 4 fit neatly under the cover with room for soft bags around them. With the second row folded, we carried 14 boxes to the window line and 18 to the headliner before rearward visibility and hatch clearance became concerns. That translates to ~24 cu ft (6 boxes) usable to the window line seats-up, and ~54 cu ft (18 boxes) seats-down to the headliner—consistent with Subaru’s generous, square-sided layout. We noted minimal wheel-arch intrusion; the limiting factor is height, not floor area.
Load management is excellent. Four metal D-rings at the floor corners are properly braced; our 1-inch ratchet straps held 50-lb boxes without flex or creak. Two grocery hooks keep smaller items upright, and a 12V outlet sits on the right wall. Quick-release levers in the cargo area drop the 60/40 backs flat in one motion.
The optional rubber tray has a raised lip that trapped a tipped one-gallon jug during an emergency stop test (0.86 g), and the roller-shade cover can be latched halfway to segregate layers. We’d add a cargo net if you routinely stack above the seatback height. Roof rack usability is a standout. Subaru’s integrated crossbars swing out tool-free in under two minutes; our measured bar spread ranged from 30.7 to 40.2 inches.
Dynamic roof rating is 150 lb. We mounted a Thule Motion XT L (16 cu ft) solo in 7 minutes; full hatch clearance was possible when the box was slid forward one notch, with no antenna contact. Highway loop at 70 mph showed a 2–3 dB increase in wind noise and a 1.8 mpg penalty (from 30.1 to 28.3 mpg indicated). Crosswind stability remained solid, and the low roof height made loading manageable without a step stool for our 5'9" tester.
Verdict: The Outback remains one of the most practical wagons for real cargo work. It swallows a meaningful count of standard boxes seats-up, goes deeper with a flat fold, and its built-in crossbars make roof cargo painless. If you haul tall items under a cover, consider mixing box sizes to exploit the full width; frequent roof users should budget for fairing-equipped boxes to cut wind noise. For families and gear-heavy weekends, it’s an easy recommendation.
