Sea to Summit Big River Dry Backpack

The Sea to Summit Big River Dry Backpack is a waterproof, roll-top pack built for paddle sports and motorcycle touring, using 420D nylon fabric with a 10,000mm hydrostatic head and fully taped, double-stitched seams. A triple-coated oval base adds abrasion resistance and water-shedding durability where the pack takes the most punishment. Three sizes (30L, 50L, and 75L) cover day trips through multi-day expeditions.

Waterproofing That Holds Up to Immersion

The Big River's roll-top closure is secured with Sea to Summit's Field Repair Buckles, which can be swapped out in seconds using only a Phillips screwdriver. That replaceability matters on a week-long canoe trip or a remote moto route where a broken buckle would otherwise end the waterproofing. The closure pairs with double-stitched, fully taped seams and a 10,000mm hydrostatic head rating, so the pack holds up to sustained rain, spray, and submersion rather than just light moisture.

Built for Rough Handling and Lashing

The 420D nylon shell is bonded to a white TPU interior lining, giving the fabric both its waterproof rating and resistance to abrasion, tearing, and puncture. The ovalised base receives a triple coating for the extra wear it takes when the pack is set down on rock, gravel, or a boat deck. Lash rails and a grab handle let the pack be secured to a kayak, bike, motorbike, or roof rack without additional rigging, useful when the pack needs to stay put through rapids or a rough trail section.

Visibility and Carry

The white TPU interior laminate reflects light into the pack, making it easier to locate gear without unpacking everything. The EVA foam harness is non-adjustable, a deliberate choice for durability and simplicity on demanding days, and includes a sternum strap and a removable 38mm webbing waist strap to keep the load stable. The oval base shape also prevents the pack from rolling when set down and allows easier stacking with other gear.

Features

• 10,000mm hydrostatic head: 420D nylon bonded to a white TPU lining with fully taped, double-stitched waterproof seams
• Field Repair Buckles: roll-top closure buckles replaceable in seconds with a Phillips screwdriver
• Triple-coated oval base: extra abrasion and water-shedding protection at the base; ovalised shape aids stacking and prevents rolling
• Lash rails and grab handle: for securing to kayaks, bikes, motorbikes, and roof racks
• White TPU interior laminate: reflects light for greater visibility of packed gear
• Non-PFAS construction: non-PFAS PU coating throughout

Specifications

Who This Is For and Isn't

The Big River Dry Backpack suits paddlers (kayakers, canoeists, rafters) and motorcycle tourers who need a rugged, waterproof pack that can be lashed to a boat or bike and withstand sustained water exposure. The 30L works for day trips; the 50L and 75L cover multi-day expeditions where keeping gear dry is non-negotiable.

The Big River does not have an adjustable harness or internal pockets, so buyers who need a customizable fit system or organized interior compartments should look elsewhere. The waist strap is not a load-transferring hipbelt and is not suited for carrying heavy loads over long distances beyond approximately 12 kg. The 75L size is available only in Picante.

Common Questions

Is the harness on the Big River Dry Backpack adjustable?

The Big River Dry Backpack uses a non-adjustable EVA foam harness. Sea to Summit chose a fixed harness for durability and simplicity on demanding days of hauling gear, pairing it with a sternum strap and a removable 38mm webbing waist strap to keep the pack stable during active use.

How much weight can the Big River Dry Backpack carry?

The Big River Dry Backpack is fitted with a waist strap rather than a load-transferring hipbelt. For short carries, a load up to approximately 20 kg is manageable; for longer distances, a limit of around 12 kg is more appropriate, depending on the individual wearer.

Does the Big River Dry Backpack have inside pockets or compartments?

The Big River Dry Backpack has no internal pockets or dividers. The white TPU interior laminate reflects light to help locate gear, and Sea to Summit recommends packing smaller items in dry bags or stuff sacks to keep them organized and easy to find inside the main compartment.

What makes the Big River Dry Backpack's closure waterproof?

The Big River Dry Backpack uses a roll-top closure secured with Field Repair Buckles, combined with double-stitched, fully taped seams and a 420D nylon shell bonded to a TPU lining rated to a 10,000mm hydrostatic head. Together these elements create a seal rated for sustained rain, spray, and water immersion.

Can the Field Repair Buckles on the Big River Dry Backpack be replaced in the field?

The Field Repair Buckles on the Big River Dry Backpack are designed to be replaced in seconds using only a Phillips screwdriver, with no adhesives or special tools required. This means a damaged buckle can be swapped out mid-trip without ending the pack's waterproof seal.