Quick Answer: The Thule Force XT L ($879.95, 16 cubic feet) is the best rooftop cargo box for most vehicles with open roof rack space. If a rooftop tent already occupies that space — which it does on most SUVs and wagons — the Yakima EXO SwingBase with GearLocker ($898, 10 cubic feet) hitch-mounts instead and adds storage without touching the rack your tent needs. Budget shoppers should look at the Rightline Gear Sport 3 soft carrier (~$140, 18 cubic feet), which straps on with or without a rack at all.
A rooftop cargo box solves a real problem for overlanders: a hardshell tent already eats into your interior cargo space when folded down, and a family trip’s gear pile doesn’t shrink to match. But the honest starting question isn’t which box to buy — it’s where it’s going to mount, because for a large share of rooftop tent owners the answer is “not on the roof.” Below we cover the best pick for an open roof, the best pick when your rack is already spoken for, and the budget option that works either way. If you haven’t sorted the rack itself yet, check our best roof rack guide first — load rating there determines what any of these boxes can actually carry.
Rooftop cargo boxes by the numbers
- A typical crossover’s dynamic roof load caps around 165 lbs, per Thule and Yakima’s published rack specs — that has to cover the box (40-60 lbs empty for most hardshell models), the crossbars, and everything packed inside, all at once.
- A roof box costs 2-4 mpg on the highway, a widely reported real-world hit from the added aerodynamic drag — worse at higher speeds, which is part of why many rooftop tent owners route extra gear to a hitch-mounted box instead of stacking a second drag source on the roof.
- Hardshell boxes run $140-$949 across the picks below, from the Rightline Gear Sport 3 soft bag to the Yakima SkyBox NX XXL, with capacity ranging 10-18 cubic feet.
Cargo box picks at a glance
| Product | Mount type | Best for | Capacity | Price |
|---|---|---|---|---|
| Thule Force XT L | Roof crossbars | Best overall (open roof) | 16 cu ft | ~$879.95 |
| Yakima EXO SwingBase + GearLocker | 2in hitch receiver | Best for rooftop tent owners | 10 cu ft | ~$898 |
| Rightline Gear Sport 3 | Roof rack or door-frame clips | Best budget | 18 cu ft | ~$140 |
| Yakima SkyBox NX XXL | Roof crossbars | Best for large families | ~18 cu ft | ~$949 |
| Yakima SkyBox 16 Carbonite | Roof crossbars | Best value hardshell | 16 cu ft | ~$719 MSRP |
1. Thule Force XT L — Best Overall
Thule Force XT L
- 16 cubic feet, enough for a family's soft luggage and gear on a multi-day trip.
- Dual-side opening — load from either side of the vehicle, useful in tight parking.
- Fits Thule's crossbar system and most factory crossbars with the right adapter.
- Integrated locks on the latches, keyed the same as other Thule accessories.
The Force XT L is the box to buy if your roof rack isn’t already carrying a rooftop tent — it’s a proven, widely-reviewed hardshell with 16 cubic feet of locking, weatherproof storage that mounts to nearly any crossbar setup on the market. Dual-side opening means you’re not always unloading from the same side, which matters more than it sounds like once you’re packing a full car at a trailhead. At $879.95 it’s not cheap, but it holds resale value well and the aerodynamic shape costs less mileage than a boxier budget alternative.
Get your camp setup sorted before the trip — try Amazon Prime free for 30 days so the smaller straps and mounting hardware ship in two days instead of holding up the install.
2. Yakima EXO SwingBase + GearLocker — Best for Rooftop Tent Owners
Yakima EXO SwingBase + GearLocker
- Mounts to a standard 2-inch hitch receiver, not the roof rack.
- GearLocker cargo box adds 10 cubic feet of locking, weatherproof storage.
- Swings away from the rear hatch for full trunk access without removing the box.
- Modular EXO system also accepts bike trays and a TopShelf rack instead of the box.
This is the pick that actually solves the rooftop tent owner’s problem instead of ignoring it. Most hardshell tents take up the entire usable crossbar span on an SUV or wagon, so a second roof box simply isn’t an option — the EXO SwingBase sidesteps that by mounting to the hitch receiver instead. At $499 for the base and $399 for the 10-cubic-foot GearLocker box, it’s more expensive than a comparable roof box for less capacity, but you’re paying for the only mount point most RTT rigs have left. The swing-away hinge is the detail that matters day to day: you can still open the rear hatch fully without unbolting anything, which a fixed hitch cargo platform can’t do.
3. Rightline Gear Sport 3 — Best Budget
Rightline Gear Sport 3
- 18 cubic feet — more capacity than either hardshell pick above, for a sixth of the price.
- Attaches with or without a roof rack, using door-frame clips as a backup mount.
- Welded, waterproof seams and a coated zipper, per Rightline Gear's published spec.
- Folds flat for storage when not in use — no garage space taken between trips.
If you’re not ready to spend $700+ on a box you’ll use a handful of times a year, the Sport 3 is the honest answer. It holds more volume than the Force XT L or SkyBox 16 for around a sixth of the price, and because it straps directly to door-frame weather molding it works even on vehicles with no roof rack at all. It won’t survive being crushed under a rooftop tent’s footprint, so it’s a front-of-roof or truck-bed solution for RTT rigs rather than a same-span companion — but for anyone without a tent occupying the rack, it’s the lowest-risk way to find out if you actually need a hardshell box before buying one.
4. Yakima SkyBox NX XXL — Best for Large Families
Yakima SkyBox NX XXL
- Largest capacity in Yakima's SkyBox NX lineup, built for multi-family or extended trips.
- SKS locks integrated into both latches, keyed alike with other Yakima locks.
- Dual-side opening, same convenience trade Thule offers on the Force XT line.
- Aerodynamic shell profile designed to cut wind noise versus boxier budget shapes.
At $949, the SkyBox NX XXL is the most expensive box here, and it earns that price with the most usable volume of the roof-mounted options — the one to buy if you’re outfitting a full family trip on top of whatever’s already packed inside the vehicle. It’s still a roof-rack-only mount, so the same rooftop-tent caveat applies: this box needs its own clear crossbar span, and most tent-equipped rigs won’t have one to spare. For anyone with an open roof and genuinely more gear than the Force XT L or SkyBox 16 can hold, it’s the size to step up to.
5. Yakima SkyBox 16 Carbonite — Best Value Hardshell
Yakima SkyBox 16 Carbonite
- 16 cubic feet, matching the Thule Force XT L's capacity at a lower published price.
- SKS lock system standard, no separate lock purchase needed.
- Textured Carbonite finish resists scratches better than gloss alternatives.
- Frequently discounted at REI and other retailers during seasonal sales events.
The SkyBox 16 matches the Force XT L’s 16 cubic feet at a lower MSRP, and it’s the box most likely to show up discounted during REI’s sales events or similar retailer promotions — worth a price check before you commit to either brand at full price. Functionally the two are close: both lock, both mount to standard crossbars, both cut wind noise better than a flat-sided budget box. Pick based on which crossbar system you’re already running, since Thule and Yakima each fit their own hardware most easily.
How to choose a rooftop cargo box
Start with what’s actually available on your roof, not with the box you like best. If a rooftop tent already occupies your crossbar span, a roof box is off the table for that vehicle — go straight to a hitch-mounted option like the Yakima EXO SwingBase or accept a soft bag strapped to whatever open bed or roof space remains. If your roof is genuinely open, choose capacity based on trip length and party size: 16 cubic feet (Thule Force XT L or Yakima SkyBox 16) covers most couples and small families, while 18+ cubic feet (Yakima SkyBox NX XXL) suits a full family loadout. And if you’re not sure you’ll use a box often enough to justify $700+, the Rightline Gear Sport 3 answers that question for $140 before you commit to a hardshell purchase.
The bottom line
For most vehicles with an open roof, the Thule Force XT L is the safest pick — proven, lockable, and sized right for a typical trip. But the more useful insight for this site’s audience is the mount-point problem itself: a rooftop tent usually forecloses a roof box entirely, and the Yakima EXO SwingBase with GearLocker is the real answer for that rig, not a smaller roof box squeezed in beside the tent. Whichever you choose, check your vehicle’s actual dynamic roof load rating before loading it — our rooftop tent weight guide breaks down exactly how that number gets split between a tent, a rack, and everything else you’re trying to carry.