What Size Cargo Box Fits a Forester?

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The Forester has the tallest roof of the three current Subaru models, so a cargo box adds more reach to loading than it would on a Crosstrek or Outback. Capacity-wise, the Forester can hold its own against the Outback — the difference is that on a Forester, going up a size stacks extra height on top of a roof that’s already the tallest of the three.

Here’s how to size a box that works with the Forester’s height instead of fighting it.

Quick Picks

• Best overall: Yakima SkyBox 18 — around 18 cubic feet, the easiest size to live with on a Forester.
• Best for families and gear-heavy trips: Thule Motion 3 XL — more capacity, but expect more reach when loading.

Choosing a Cargo Box Size for a Forester

The SkyBox: The Easiest Default

For most Forester owners, an 18-cubic-foot box like the Yakima SkyBox 18 is the practical starting point — enough room for road trips and camping gear without adding more height than necessary on a vehicle that’s already the tallest of the three Subarus.

Sizing Up: What Actually Changes

The Forester can technically fit an XL box the same as an Outback can — the roof space is there. What’s different is the loading experience: the Forester’s roof is already the tallest of the three, so a taller box on top of it means more real reach for anyone loading solo. The Thule Motion 3 XL works well for families who need the capacity, but a step stool earns its keep here more than it would on an Outback or Crosstrek.

Hatch Clearance Still Matters

Box length, not cubic feet, is what causes hatch interference. A box mounted too far back can catch the rear hatch on the way up regardless of size — adjusting crossbar spread and sliding the box forward usually fixes it without needing to size down.

Forester vs Outback vs Crosstrek Cargo Box Sizing

Model	Roof Length	Loading Height	Realistic Ceiling
Forester	Moderate	Tallest — more reach to load	Large; XL adds real loading effort
Outback	Longest of the three	Moderate	XL boxes, with room to spare
Crosstrek	Shortest, narrowest	Lowest, easiest to reach	Medium-Large; XL is a stretch

The Forester isn’t the easiest to load, but it’s not far behind the Outback on capacity — the tradeoff shows up in loading effort, not available roof space.

Cargo Box Size by Forester Generation

Third-generation Foresters (2009-2013) and fourth-generation (2014-2018) both handle medium and large boxes well, with XL sizes needing closer attention to hatch clearance. Current-generation (2019-present) Foresters offer the most flexibility, including XL with proper fitment. The Forester Wilderness shares the standard model’s roof dimensions, but its added ride height makes solo loading a bit more work — worth planning around if you load without help.

Common Mistakes Forester Owners Make

• Not accounting for the extra reach when loading solo. The Forester’s tall roof means more lifting than an Outback or Crosstrek — a step stool helps if you load alone often.
• Buying XL without trying it on for size first. The capacity is there, but the loading height adds up fast on a Forester.
• Leaving the box mounted year-round. It adds drag and wind noise even empty.

FAQs

What size cargo box fits a Subaru Forester?

Most Foresters comfortably run 15-20 cubic feet. XL boxes are possible, but the Forester’s height means loading takes more effort than on an Outback of the same box size.

Does the Forester’s height limit box size?

Not really — it limits loading ease more than size. The roof can physically hold the same boxes an Outback can; reaching them is what takes more effort.

Does the Forester Wilderness fit larger boxes?

Yes, the roof dimensions match the standard Forester. Its taller ride height just adds a bit more to the reach.

Do I need aftermarket crossbars for a larger box?

Not always — factory crossbars handle most box sizes fine. Aftermarket bars help mainly if you need more adjustment for hatch clearance.

Final Thoughts

The Forester holds its own on capacity against an Outback — the real difference is loading effort, not roof space. An 18-cubic-foot box is the easy default; sizing up to XL works fine, but expect to reach further to do it. Match the size to how often you actually need the extra room.

Recap: Best Cargo Box Sizes for a Subaru Forester

• Yakima SkyBox 18 — best overall
• Thule Motion 3 XL — best for families and gear-heavy trips

Related Guides

• What Size Cargo Box Fits an Outback?

• What Size Cargo Box Fits a Crosstrek?

• What Crossbar Length Do You Need?

• Best Crossbars For Kayaks