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Choosing the Correct Dry Bag

Choosing the Correct Dry Bag

With the range of Sea to Summit’s dry storage options spanning from the ultra-light 15 Denier Ultra-Sil® Nano to the new super burly 600 Denier Hydraulics, it’s important to know which dry sack is the right choice for your intended use and activity.

For instance, feather-weight fabrics are ideal for use inside a pack, but in environments where the dry sack may be rubbing against something (such as the bottom of a boat) more heavy duty fabrics are required.

We have 11 different types of Dry Bags here at Sea to Summit. Here is a very basic description of each – starting with the lightest and ending with the most rugged.


1) Ultra-Sil Nano Dry Sacks are made of featherweight 15 Denier siliconized nylon with a newly-designed lightweight buckle. Designed for the gram-conscious backpacker, these minimalist dry sacks keep your gear dry and organized inside a pack, yet weigh less than many ‘ultralight’ stuff sacks. Not suitable for boating/marine use.

2) Ultra-Sil Dry Sacks are constructed using extremely light-weight siliconized 30 Denier CORDURA brand nylon. They are intended for use inside a backpack or similar bag, where they are great for keeping sleeping bags, clothing and other gear dry and tidy. Not suitable for boating/marine use.

3.) UltraSil eVent Compression Dry Sacks are made of 30 Denier CORDURA brand nylon with an eVent base. They are the super-lightweight version of the 70 Denier nylon eVent Compression Dry Sack and are approximately one-third lighter. Great for compressing sleeping bags and insulated clothing. Not intended for external use (ie mounted externally on a backpack, or for bikepacking, or for river/marine use.

A quick note about using dry sacks as ‘bear bags’. Ultralight hikers in particular attempt to save every possible gram, and may, therefore, want to use UltraSil Nano and UltraSil Dry Sacks to keep food out of the way of bears and other animals at night. If this involves hauling the bag up through tree branches, the probability is that featherweight/very lightweight fabric will snag and tear at some point. We would therefore not recommend UltraSil Nano and UltraSil Dry Sacks for this use.


1) View Dry Sacks feature the same 70 Denier CORDURA brand nylon as regular Lightweight Dry Sacks but have a welded-in window made of Thermoplastic Polyurethane (TPU). Ideal for group trips or longer backpacking excursions – anywhere where you quickly need to identify the contents of your dry sacks.

2) Lightweight Dry Sacks are made of 70 Denier nylon. They are tough, yet still light enough to work well in backpacking use. The flexible fabric makes them easy to stuff into tight areas – ideal bags for general boating / outdoor use.

3) eVent Compression Dry Sacks / eVac Dry Sacks are made with 70 Denier nylon and work really well for any compressible item (sleeping bags, clothing) which needs to be squeezed down as small as possible yet stay dry. Air just squeezes out through the eVent base, but water can’t get in.


1) Big River Dry Bags are made from tough, 420 Denier ripstop nylon laminated to a TPU film. They have a very high tear strength and abrasion-resistance, which makes them the perfect choice for whitewater rafting/boating/motorcycle touring. Lash patches on the sides make attachment to a raft or motorcycle rack really simple.

2) Dry Packs – Rapid 26L, Flow 35L – are made with the same fabric as the Big River Dry Bags and have a roll top closure. However, they are fully featured, tough backpacks with quick-drying shoulder straps and a comfortable ergonomic back panel.

3) Stopper Dry Bags are made of 210 Denier nylon with TPU lamination on the outer face for increased durability. The fabric is UV resistant, won’t crack in extreme cold and is flexible. Despite their lightweight, they are suitable for river/marine applications. Completely welded construction. Features the Field Repair Buckle. Great for canyoneering, climbing, ski touring, SUP tours, bike commuting.

4) Clear Stopper Dry Bags are RF welded and made with a Thermoplastic Urethane (TPU) film with a 210 Denier laminated nylon fabric base. The high strength TPU film is durable and flexible and allows you to easily see the contents. Ideal for boating/marine environments. Completely welded construction. Features the Field Repair Buckle.

5) Hydraulic Dry Bags / Hydraulic DryPacks are designed for the most extreme conditions that demand toughness and abrasion resistance. They are made of a 600 Denier polyester carrier material with TPU laminated on the inner and faces. Completely welded construction including the lash patches. Features the Field Repair Buckle.

A note about submersion – be aware that any roll-top dry sack, regardless of manufacturer, can only be submerged to a certain depth for a short period. Longer/deeper submersion and pressure can cause water to seep through the roll-top closure. This is true for dry sacks from all brands, not just Sea to Summit.

If you will be transporting electronics or other sensitive items in very wet/potential submersion situations it is essential to ‘double bag’ these items: place them in one dry sack and carefully roll and seal the roll-top closure. Now place this in a second dry sack and roll and seal the roll-top closure. If you are using dry sacks to store electronics in areas of high humidity, be aware that moisture vapor can condense inside any waterproof enclosure if the temperature drops. To avoid damage to the electronics, place a desiccant (for instance, a silica-gel pack) in the dry sack along with the electronic items.

14 thoughts on “Choosing the Correct Dry Bag

  1. avatar Baz says:

    G’Day Sage

    Thanks for reaching out to us! So we can make some recommendations for you, can you please let us know (via an email to What you will carry in the pack | What weather conditions the pack will be used in | Whether the pack will be submerged (and if so, for how long) | Where you are located

    We’ll be happy to share our thoughts as to which pack might work best for you.


    The Sea to Summit team

  2. avatar Sage says:

    I was told by my professor to get a dry pack for my upcoming marine biology field course. Which of your products do you suggest for me?

  3. avatar Baz says:

    G’Day Betty,

    Thanks for your question. If you are looking to store your personal belongings on the beach while you swim, any of the following dry bags would work well: Lightweight Dry Sack, Big River Dry Bag, Stopper Dry Sack. If you are intending to swim with a dry sack (which may well involve the dry sack being pulled under the surface of the water), there is no single dry sack which will provide adequate waterproof protection for sensitive items such as electronics. Phones, cameras and even car key fobs should be ‘double bagged’ – placed in one dry bag (roll the closure three times and click the buckle closed) then placed in a second dry bag (again, three rolls of the roll-top closure).

    If you have any questions on the above, shoot us an email at

    The Sea to Summit Team

  4. avatar Baz says:

    G’Day Trev,

    Thanks for your question. The Trailhead Th III Regular is supplied with a size Large Stuff Sack (15L), which means its mildly compressed volume is very close to 15 Liters. It would be a little tricky to fit the Th III into the 14L Size Medium eVent Compression Dry Sack – you would find that the sleeping bag may project out through the roll-top closure and prevent you rolling it three times to close it. Fitting the Th III into a 10 Liter Size Small eVent Compression Dry Sack would be practically impossible.
    Especially if you are planning on using the Trailhead in colder temperatures (it is rated to 20°F / -7°C), you might find that having more room in a compression dry sack (rather than less) can be quite helpful as fingers lose their dexterity – you might want to consider the 20 L size Large eVent Compression Dry Sack. This would compress the Trailhead down to around 10 Liters (the same compressed size you could expect from the Medium).

    If you would like more details, shoot us an email at

    The Sea to Summit Team

  5. avatar Trail Trev says:

    I’ve just updated to the Trailhead 3 regular sized sleeping bag. Which Event Compression bag is the best fit for the sleeping bag? I think the bag is around the uncompressed 12litres, so it should easily fit in the 14L compression bag or should I look at cramming it into the 10L Event compression bag?
    Thanks for your help.


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