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PADI Scuba Instructor
Hunter Bierce is a PADI Scuba Instructor and multidisciplinary outdoor professional.


Sea To Summit Hydraulic Dry Waterproof Backpack

Sea to Summit has designed a dry bag that has all the hallmarks of a hiking backpack in the Hydraulic Dry Pack 65L. Lugging a dry bag with anything more than 50L through a waterfall or storm in the Cascades can be a pain in the butt, therefore we got this waterproof backpack with hiking straps.

Intended as a premium product at a premium price, does it do the job? For years, Sea to Summit has garnered praise for its innovation and the Hydraulic springs from this tradition. We tested it out to see if it’s a worthy addition to the S2S stable.

Our Overall Review

We have thoroughly tested - and read reviews from other experts and users. In summary, this is what we think:


Reasons to buy

  • Portable and comfortable carry system
  • Durable build can withstand abrasions and unpredictable conditions
  • UV resistant, PVC free
  • Available in a few different sizes
  • Customizable straps and supports

Reasons NOT to buy

  • Roll top could have more room for another fold
  • On the expensive side of the drybag spectrum
  • No sweat-stopper or aeration pad for the back


I love saving money and cutting corners wherever possible with my outdoor gear. But there are a couple of pieces of equipment where I refuse to compromise on quality- dry bags being chief among them. I’ve been burned (or rather, soaked through) too many times to trust my down, phone, and dry food to anything but the best.

When faced with Sea to Summit’s wearable heavy-duty bag, I came in with high hopes and expectations. Splitting the difference between performance and practicality, the Hydraulic is an excellent compromise for trips with technical approaches and low-likelihood submersion.

See the complete list of the best Waterproof Backpacks here!

Sea To Summit Hydraulic Dry Blue At the Sand

Sea To Summit Hydraulic Dry Waterproof Backpack: Key Specifications

  • Laminated 600D fabric and welded seams
  • Adjustable, removable, EVA-foam padded harness
  • Welded TPU lash/tie-down points
  • Classic rolltop seal system
  • Cylindrical shape, oval bottom
  • Available in 35, 65, 90, and 120L sizes

Where to Buy:


Water resistance is one of the critical criteria for any drybag worth its salt. Unfortunately, that’s the one area we’ve had consistent issues with the Hydraulic Dry Pack. Though it gets the job done for splashes, torrential rain, dunks, and other assorted drips and dives–particular attention needs to be paid to locking to ensure total waterproofing.

To be fair, this bag is neither intended nor designed to withstand prolonged submersion, but that doesn’t mean you should disregard it. For whitewater trips with a high likelihood of flipping, you’re probably better off opting for something completely leakproof.

The issue lies in the roll top that has rubberized lips with insufficient space to fold down the requisite 3 times. When folding, I almost run out of real-estate before reaching the shoulder straps. Waterproofing is likely only when being meticulous here.

Still, for more casual fly fishing trips, a day on the motorboat, or backpacking and canyoneering in light rain or around waterfalls, it’s a great product.

Sea To Summit Hydraulic Dry Sand With Flowers Behind

Transport and Usability

Though it may flag in terms of waterproofing when submerged, you certainly can’t fault the Hydraulic when it comes to comfort and transport when the system works.

In my experience, additional buckles and handles are a massive boon for loading boats and supplies and have the additional benefit of saving on busted rolltop buckles. That’s not to mention hauling gear down precipitous mule trails if you’re planning on launching a trip from the bottom of a canyon. That’s where the shoulder straps shine: carrying a dry bag anyplace you would rather have a backpack.

There are a couple of discrepancies between models–namely, the hip belt of the 35L variation is quite a bit smaller than the full backpacking style belt employed in their larger models.

Conceptually a dynamic, removable adjustable harness system is a great idea, but in practice, the Hydraulic needs a little more fine-tuning before it gets my enthusiastic endorsement. The shoulder straps tend to slip after they get wet and sometimes even during regular weighted use. While ultimately still functional, it’s a sore disappointment when the focal features of a bag are the one that gives you issues.

Sea To Summit Hydraulic Dry Buckle


Next to waterproofing, durability is the most significant factor I consider when deciding between dry bags. These factors go hand in hand, as a perforated bag is far from a dry one. The Sea to Summit Hydraulic Dry Pack excels in this regard and spares no expense when it comes to the integrity of the build. With the welded seams and 600D fabric, you can tell at a glance the Hydraulic is several steps beyond a simple roll-top nylon.

Built to the specifications of a genuine expedition pack, the Hydraulic can withstand the trials of the river just as much as its high-abrasion overland adventures. Everything except the straps and harness system is fully welded to the bag, so ripping off buckles and tie-down points is much less of a concern than if they were simply glued down.

Though the Hydraulic Dry Pack is a serious piece of gear, it’s not impossible to rip through if you’re heedlessly dragging it over granite or through briar patches. Have high durability expectations but keep them within reason.

Sea To Summit Hydraulic Dry Handle


The removable backpack system has been mentioned a few times, but it’s worth getting into more detail here. The harness system connects to the drybag itself through a herringbone pin that slots between the shoulder blades, additionally supported by a series of aluminum buckles around the tops of the shoulders and the hip belt. Sea to Summit includes an extra buckle in their field repair kit should you suffer any unexpected blowout in the midst of adventure.

The harness itself is decidedly lightweight and is built conceptually around the idea of drying out quickly. The carry system has the added benefit of promoting airflow, keeping you cool while hauling your bag around. In my experience, it’s no fun feeling suffocated by heavy fabrics as you race against the rising sun. I thought that the hip belts on the higher-volume models were an excellent addition that I’m not used to seeing from anything less than a dedicated backpack.

When you’re not hauling the Hydraulic Pack around, the bag has a few welded tie-down points to help you lash it to your gear boat or otherwise make sure that it’s secure while you’re underway. Other than that, the pack is light on features, and there are a couple of things that we’d love to see in future models, particularly for something that takes such an expedition-minded approach.

The biggest issue with the Hydraulic Pack next to the finicky harness system is there’s only one place to store gear. And only the only place to access that main compartment is through the roll top. The bag would greatly benefit from both a waterproof side access and exterior pockets to grab gear on the go. As it stands, it’s tough to access anything on the fly, and this is a big problem for something seeking to be more than just another dry bag.


The Sea to Summit Hydraulic Dry Pack is expensive for a dry pack, but it’s right on track for waterproof duffels and heavy-duty expedition bags. Herein lies the problem- the Hydraulic falls into the trap of aiming to be the best of both worlds while falling short of being great at either. If the shoulder straps were more effective and the bag was truly waterproof, I think that the price per practicality would be unmatched, but for now, I’d say it’s a little on the expensive side for what you’re getting.

Value ultimately hinges on how you’re going to use it. If your pack is just going to sit in the bottom of your raft or canoe, I think you’d be better off opting for something more affordable, but for canyoneering or hiking in warm, wet places, it’s worth taking another look. Opting for a waterproof backpack instead of lining your standard pack with several smaller dry bags is also a great way to save weight and money.

Sea To Summit Hydraulic Dry Adjust For Transport


Though it may have its issues, Sea to Summit’s Hydraulic Dry Pack is an innovative midpoint between a dry pack and a fully realized expedition bag. With a bit of post-factory fiddling with the shoulder straps, you could have a great solution to your canyoneering and tropical hiking needs. But for trips where bombproof watertight protection is more important than portability, you’re likely better off opting for something more practical and affordable.

See the complete list of the best Waterproof Backpacks here!

What We Like

  • Portable and comfortable carry system
  • Durable build can withstand abrasions and unpredictable conditions
  • UV resistant, PVC free
  • Available in a few different sizes
  • Customizable straps and supports

What We Don’t Like

  • Roll top could have more room for another fold
  • On the expensive side of the drybag spectrum
  • No sweat-stopper or aeration pad for the back

Where to Buy:

Where to Buy:

FAQ – Frequently asked questions about Sea to Summit Hydraulic Dry Bag

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    How to close a dry bag?

    The vast majority of dry bags will be the roll-top variety, and once you get the hang of using them, the process is relatively consistent regardless of the brand of bag you use. Here’s a quick and easy overview of the process.

    How to close a dry bag:

    • Draw the mouth of the bag straight up, and hold by either edge of the opening
    • Push all of the air out of the remaining space in the bag, and draw the excess material straight up
    • Roll the mouth of the pack at least three times to create a waterproof seal, and buckle at the top

    Most dry bags only need to be rolled three times to create a waterproof seal, but make sure to check the specifications of your specific model to make sure you have a dependable way of keeping your most essential items dry.

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    Are Sea to Summit dry bags good?

    Sea to Summit has a reputation for their wide range of adventure-oriented dry bags. From small sacks that add an extra degree of protection to your electronics to burly adventure duffles, they have you covered. To see our favorites from Sea to Summit and how they stack up against other big names in the industry, head over to our best dry bags page.

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    Are Sea to Summit dry bags waterproof?

    Sea to Summit bags are waterproof, but the degree of resistance depends on the style and make of the specific bag you’re interested in. Some bags, such as their Hydraulic Dry Pack are built only to resist splashes and brief submersion, while others are bomb-proof shelters for your phones, keys, and other essentials.

    For more on our favorite Sea to Summit dry bags, and to see how they stack up against the competition at large, head over to our best of page for an in-depth look at our favorites across the industry.

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    What is the best dry bag?

    The best dry bag is the one that fits your needs and intentions the most closely. Not all dry bags are built the same, and the best one for the bottom of your kayak on your upcoming whitewater trip isn’t going to look much like the overbuilt expedition bag you’ll want for extended travel. That being said, here are a few of our favorites from different styles across the industry.

    Best Dry Bags:

    • Osprey Ultralight 12 Dry Sack
    • Yeti Panga
    • Sea to Summit Big River Dry Bag
    • Sea to Summit Event Compression Dry Sack
    • Earth Pak Waterproof Dry Bag
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    What size dry bag do I need?

    Your dry bag needs will vary radically depending on what you intend on using them for. Those in search of something to store their phone, wallet, and keys would be best served by anything around the 5L range. For overnight trips, you’ll want to start looking in the 25-30L range; trips for more than one person, something around 50-60L, becomes more appropriate.

    If you’re curious about dry bags and how to narrow down the vast sea of options out there to the right model for you, take a look at our best of page to see side by side comparisons of our favorites across the board.


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