# Dry Bags, Waterproof Stuff Sacks and Pack Liners (2026): Which One Keeps What Dry > Roll-top dry bags, light waterproof stuff sacks and pack liners compared on fabric, hydrostatic head and seams, what submersion does, and where an IP rating applies. - Source: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks - Publisher: WildProofLab (https://wildprooflab.com) - Published: 2026-09-29 - Category: rain-wind - Tags: dry bags, roll top dry bag, waterproof stuff sack, pack liner, backpack liner, kayak dry bag, IPX8 - Method: picks chosen from Amazon listings and brand specs; not hands-on tested; current Amazon prices are on the page; content checked 2026-09-29. - Quick answer: Inside a backpack, line the whole pack with a roll-top liner such as the Six Moon Designs 50L, then sort gear into light stuff sacks. On a boat deck, use a heavy roll-top bag like the Sea to Summit Big River: 420D nylon with a TPU lining and a 10,000 mm hydrostatic head, per Sea to Summit. ## Key takeaways - Roll the top at least three times: Sea to Summit rates its bags' volume with the closure rolled three times. - A roll-top is not a submersion seal. Sea to Summit says to avoid submersion because water can seep through the roll-top closure of any dry bag. - An IP rating belongs to the item that was tested. Earth Pak quotes IPX8 for the phone case in its dry bag kit, not for the roll-top bag itself. ## Products (chosen from listings, not tested) 1. **Six Moon Designs 50L Waterproof Roll Top Pack Liner** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B08NC6SCQB) — Buy it to keep everything inside a backpack dry in one step. - Pros: Sil/PU-coated 40D nylon ripstop with taped seams and a roll-top, per Six Moon Designs; 3 oz (86 g) for 50 liters, 27 by 21 by 8 in; D-ring for hanging - Cons: No hydrostatic head published 2. **Osprey Ultralight Protective Backpack Liner** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BKQGT2T1) — Buy it if you pack in Osprey's system and want a liner from the same maker. - Pros: Roll-top waterproof closure, per the listing; bluesign-approved, recycled main fabric; DWR made without PFAS - Cons: The listing gives no volume, weight or waterproof figure 3. **Sea to Summit Lightweight Dry Bag, 8L** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BVWJJCCC) — Buy it for the sack that holds your sleeping bag or electronics, in a pack or on a boat. - Pros: 70D nylon with a PU coating rated to 10,000 mm hydrostatic head, per Sea to Summit; Double-stitched, tape-sealed seams; Hypalon roll-top; oval base; Sea to Summit says it is suited to paddle sports - Cons: Heavier than the Ultra-Sil sacks for the same volume 4. **Sea to Summit Big River Dry Bag, 13L** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BVW6MR54) — Buy it for gear strapped to a kayak, canoe, raft or motorcycle. - Pros: 420D nylon bonded to a TPU lining, 10,000 mm hydrostatic head, per Sea to Summit; Triple-coated base, reinforced taped seams, multiple lash points; Grab handles and an oval base that resists rolling - Cons: 0.43 lb for 13 liters, per the listing; too heavy to carry many inside a pack 5. **Sea to Summit Ultra-SIL Dry Bag Set (3L, 5L, 8L)** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BZJPDBKX) — Buy it to split clothes, food and first aid inside a lined pack. - Pros: 30D Ultra-Sil Cordura nylon, 2,000 mm waterhead, per the listing; Taped seams, Hypalon roll-top; translucent so you can see what's inside; Three sizes from 0.07 to 0.09 lb each - Cons: Sea to Summit says Ultra-Sil bags are not intended for paddle or watersports use 6. **Sea to Summit Ultra-SIL Dry Bag, 8L** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BXDTYY24) — Buy it for one light sack for clothes or a quilt inside a pack. - Pros: 0.09 lb for 8 liters, per the listing; 2,000 mm waterhead; Double-stitched, tape-sealed seams - Cons: Thin 30D fabric; not for paddling, per Sea to Summit 7. **Earth Pak 20L Waterproof Dry Bag** (details: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B06XD2N14J) — Buy it for a day on a boat or beach when you also want a phone pouch. - Pros: 500D PVC roll-top bag with a 24 to 42 in shoulder strap, per the listing; Includes a phone case certified IPX8, per Earth Pak, for phones up to 6.5 in; Five-year warranty; six sizes from 5 to 55 liters - Cons: No hydrostatic head or seam details on the listing; the IPX8 claim covers the phone case only Keeping gear dry on a wet trip takes two different jobs. Inside a backpack, the pack fabric and its seams will let water through in steady rain, so something inside has to be waterproof: a liner around everything, or sacks around the things that matter. On a boat, the bag itself sits in spray and puddles and has to take abrasion. The seven picks here split along that line. **How we chose:** we did not test these bags; we read each listing and the makers' product pages, and kept only bags sold by Amazon.com or the brand's own store and in stock when we checked on September 29, 2026. ## Seven bags and liners side by side | Bag | Fabric (per maker or listing) | Hydrostatic head | Seams | Use the maker gives | Sold by | Amazon price | |---|---|---|---|---|---|---| | [Six Moon Designs 50L Pack Liner](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B08NC6SCQB) | Sil/PU 40D nylon ripstop | Not published | Taped | Inside a backpack | Six Moon Designs | see the current Amazon price on the page | | [Osprey Ultralight Backpack Liner](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BKQGT2T1) | Recycled, bluesign fabric | Not published | Not stated | Inside a backpack | Amazon.com | see the current Amazon price on the page | | [Sea to Summit Lightweight, 8L](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BVWJJCCC) | 70D PU-coated nylon | 10,000 mm | Taped | Backpacking and paddle sports | Sea to Summit | see the current Amazon price on the page | | [Sea to Summit Big River, 13L](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BVW6MR54) | 420D nylon, TPU laminate | 10,000 mm | Reinforced, taped | Paddle sports, motorcycle touring | Sea to Summit | see the current Amazon price on the page | | [Sea to Summit Ultra-SIL set](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BZJPDBKX) | 30D Ultra-Sil Cordura | 2,000 mm | Taped | Inside a pack; not for paddling | Sea to Summit | see the current Amazon price on the page | | [Sea to Summit Ultra-SIL, 8L](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B0BXDTYY24) | 30D Ultra-Sil Cordura | 2,000 mm | Taped | Inside a pack; not for paddling | Sea to Summit | see the current Amazon price on the page | | [Earth Pak 20L](https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks#product-B06XD2N14J) | 500D PVC | Not published | Not stated | Kayaking, boating, fishing | Earth Pak | see the current Amazon price on the page | Sea to Summit's figures come from its pages for the [Lightweight Dry Bag](https://seatosummit.com/products/lightweight-dry-bag), [Big River Dry Bag](https://seatosummit.com/products/the-big-river-dry-bag) and [Ultra-Sil Dry Bag](https://seatosummit.com/products/ultra-sil-dry-bag). ## Pack liner, stuff sacks, or both A **pack liner** is one big roll-top bag that sits inside the backpack. Everything goes in it, you roll the top, and the rest of the pack can soak without reaching your sleeping bag. Six Moon Designs' [50L liner](https://www.sixmoondesigns.com/products/pack-liner) is Sil/PU-coated 40D nylon with taped seams and weighs 3 ounces. **Stuff sacks** do the same for one item at a time: the sleeping bag, spare clothes, the first aid kit. They also organize, which a liner does not. The Ultra-Sil sacks are translucent, so you can see what is in each. Our approach on a wet trip: line the pack, then put the sleeping bag and the camp clothes in their own sacks inside the liner. Two layers of protection cost a few ounces, and a torn liner or a sack left open does not ruin the night. A pack cover or a poncho helps, but neither closes against the back panel, where the pack sits against your wet jacket. Our [ponchos vs rain jackets guide](https://wildprooflab.com/rain-wind/ponchos-vs-rain-jackets) covers ponchos that go over the pack. ## What the hydrostatic head on a dry bag means The number is the same measure used for rain jackets: how many millimeters of water the fabric holds back before it leaks. Sea to Summit puts the figure on each bag and says plainly what it is for. Its Lightweight and Big River bags are rated at 10,000 mm, and Sea to Summit calls the Lightweight "absolutely" suitable for paddle sports. Its Ultra-Sil bags are rated at 2,000 mm and marked "not intended for paddle/watersports use"; Sea to Summit sells them to "organize your gear inside your backpack or duffle." So match the bag to where it rides. Inside a lined pack, 2,000 mm is plenty. On a kayak deck, pick the 10,000 mm fabric and, for rough handling, the Big River's 420-denier face and triple-coated base. ## Roll it three times, and do not sink it Every roll-top works the same way: squeeze the air out, fold the stiff strip at the top over on itself, and clip the buckle. Sea to Summit's listings give each bag's volume "with closure rolled three times," which is a good minimum for any brand. A roll-top keeps out rain, spray and a splash in the bottom of a canoe. It is not built to go under. Sea to Summit's FAQ says the bag body is waterproof "however, avoid submersion since water can seep through the roll-top closure of any dry bag." If a capsize is likely, put the most important items in two bags, one inside the other. ## Where an IP rating fits in IP codes come from the International Electrotechnical Commission. The [IEC describes IEC 60529](https://www.iec.ch/ip-ratings) as the standard that grades the enclosures of electrical and electronic equipment against dust and liquids; the second numeral, from 0 to 9, rates protection against water. That makes IP codes a good fit for phone cases and electronics, and a poor fit for a fabric bag with a folded closure. None of the Sea to Summit or Six Moon Designs bags quotes one. Earth Pak quotes IPX8 for the phone case in its kit, not for the dry bag. We quote an IP rating only where the maker states it, and only for the item it names. ## Our picks **To line a backpack:** the Six Moon Designs 50L Pack Liner. A roll-top, taped seams and 3 ounces for a whole pack. The Osprey Ultralight Protective Backpack Liner is the Amazon.com-sold alternative, but its listing gives no size or weight, so check it against your pack. **For the sleeping bag and electronics:** the Sea to Summit Lightweight Dry Bag. The 70D fabric is rated to 10,000 mm, so the same bag works in a pack and on a kayak. **To sort gear inside a lined pack:** the Sea to Summit Ultra-SIL Dry Bag Set, or a single 8-liter Ultra-SIL sack. At 0.07 to 0.09 pound each, per the listings, they add little weight. **On a kayak, canoe, raft or motorcycle:** the Sea to Summit Big River. 420-denier nylon with a TPU lining, reinforced taped seams, lash points and grab handles. **For a beach or boat day:** the Earth Pak 20L, a 500D PVC roll-top with a shoulder strap and an IPX8-rated phone case, per Earth Pak. ## What goes in which bag On a wet backpacking trip, this is how we would pack: - **Sleeping bag or quilt:** its own sack inside the liner. It is the one item you cannot dry in camp. - **Camp clothes and a dry base layer:** a second sack, opened only in the tent. - **Phone, battery and map:** a small bag at the top of the pack or in a hip-belt pocket, where you can reach it without opening the liner. - **First aid kit and fire starter:** a small bright sack, easy to find in poor light. - **Wet rain gear and the tent fly:** outside the liner, in an outer pocket or on top, so they do not soak everything else. On a boat, flip the order: the heavy deck bag holds everything, and the small sacks inside it add the second layer that a capsize calls for. ## Care Dry bags fail at the closure and at pinholes. Before a trip, fill one with air, roll it shut and press it: a slow hiss finds a leak. Rinse salt water and sand out of the roll-top strip after a paddle, and dry bags open so the coating is not stored damp. A wet trip starts with the right shell on you. See our [rain jacket guide](https://wildprooflab.com/rain-wind/best-rain-jackets-for-hiking) and [rain pants guide](https://wildprooflab.com/rain-wind/rain-pants-for-hiking). Related: [rain gear for fishing and outdoor work](https://wildprooflab.com/rain-wind/rain-gear-for-fishing-and-outdoor-work) and our [rainy camping trip checklist](https://wildprooflab.com/blog/rainy-camping-trip-checklist). ## Frequently Asked Questions ### Is a trash compactor bag as good as a pack liner? It keeps water out while it is intact, but thin plastic punctures easily and has no roll-top closure, so twist it shut and check it for holes every trip. A coated-nylon liner with taped seams, like the Six Moon Designs, is built to be reused. ### What size dry bag holds a sleeping bag? Check the stuff size on your sleeping bag's spec sheet and allow for the three rolls at the top. Sea to Summit's Lightweight Dry Bag comes in sizes from 1.5 to 35 liters, per Sea to Summit. ### Will a dry bag float? A closed bag with air in it usually floats, but a floating bag is not a sealed one. Sea to Summit still says to avoid submersion, because water can seep through the roll-top. --- *WildProofLab is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. Ratings, weights and dimensions are the makers' own.* ## Sources - seatosummit.com: [Lightweight Dry Bag](https://seatosummit.com/products/lightweight-dry-bag) - seatosummit.com: [Big River Dry Bag](https://seatosummit.com/products/the-big-river-dry-bag) - seatosummit.com: [Ultra-Sil Dry Bag](https://seatosummit.com/products/ultra-sil-dry-bag) - sixmoondesigns.com: [50L liner](https://www.sixmoondesigns.com/products/pack-liner) - iec.ch: [IEC describes IEC 60529](https://www.iec.ch/ip-ratings) --- Last updated: 2026-09-29 Canonical URL: https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks How to cite: "Dry Bags, Waterproof Stuff Sacks and Pack Liners (2026): Which One Keeps What Dry", WildProofLab, https://wildprooflab.com/rain-wind/dry-bags-and-waterproof-stuff-sacks (checked 2026-09-29). Disclosure: as an Amazon Associate WildProofLab earns from qualifying purchases. Safety information summarizes public guidance and is not medical advice.