10 Best Roof Boxes 2026 in the United States

The Thule Motion 3 XXL rooftop cargo box offers a large 21 cubic feet of storage space, making it a great choice for families or travelers who need to carry extra gear. Its aluminum shell provides a sturdy and durable build, though it’s not water-resistant, so items inside might need extra protection in heavy rain. The aerodynamic, wing-shaped design with a forward-leaning nose helps reduce drag, which can save fuel during long drives.

Mounting the box is simple and quick thanks to the PowerClick tool-free system, which even signals when it's securely attached. Opening and closing is easy with a wide handle that works with one hand, adding convenience. The SlideLock system improves security by locking the box tightly and showing clearly when it’s locked. Additional accessories like an interior light and protective liner can help keep your items safe and organized.

One downside is the weight limit of 165 pounds, which might restrict very heavy loads. Also, since it’s not water-resistant, you’ll want to avoid exposing it to heavy moisture. This rooftop box is suitable for drivers looking for a spacious, easy-to-use, and secure storage solution with good aerodynamics for road trips or outdoor adventures.

The Thule Motion 3 XXL is a large roof box offering 21 cubic feet of cargo space, making it a solid choice for families or anyone needing extra storage on road trips. Its aluminum shell makes it sturdy yet lightweight compared to heavier plastic alternatives, and the wing-shaped, forward-leaning design helps reduce wind resistance, which can improve fuel efficiency a bit. Installation is user-friendly thanks to the PowerClick quick-mount system, which has a built-in torque indicator that 'clicks' when the box is securely attached — this feature helps prevent improper mounting.

Opening and closing the box is smooth with a wide handle, operable with one hand, which is convenient when loading or unloading. The SlideLock system automatically locks the lid and shows when it’s securely closed, adding peace of mind for security. While the box is water resistant, it’s not fully waterproof, so it’s best to avoid heavy rain or deep water exposure. Accessories like interior lighting and protective liners offer nice extras but come separately.

As a universal fit, it works with most roof racks, but you should still check compatibility with your vehicle’s rails. Some users might find the price higher than basic models, but the build quality and thoughtful features justify it for those who prioritize durability and ease of use.

The Thule Motion 3 XL is a large rooftop cargo box offering 18 cubic feet of space, making it suitable for families or anyone needing extra storage on road trips. Its dimensions (88" long, 18" wide, and 39" high) are quite sizable, so it fits most vehicles with roof racks but you should check your car’s roof space before buying. Made from durable aluminum, this box promises a strong shell that can handle typical outdoor conditions, though it is not water-resistant, so heavy rain might require extra precautions to protect your gear.

Aerodynamics is a key strength: the wing-shaped profile and forward-leaning nose help reduce wind drag, which can improve fuel efficiency compared to bulkier boxes. The mounting system is user-friendly thanks to the PowerClick quick-mount mechanism with a torque indicator that signals when the box is securely attached — this helps ensure a hassle-free and safe installation. Security is well covered with the SlideLock system, which automatically locks the lid and has indicators to confirm it’s properly closed. Opening and closing the box is easy with a wide handle designed for one-handed use, adding convenience when loading or unloading.

A notable drawback is the lack of water resistance, so investing in protective accessories like the optional interior box liner or storage cover is recommended if you expect wet conditions. While the box is on the heavier side due to its aluminum construction, this also contributes to its sturdiness and durability. The Thule Motion 3 XL represents a solid choice for those needing a spacious, secure, and aerodynamic roof box with easy mounting — especially suited for frequent travelers who want a reliable, high-quality carrier and can manage its size and weight.