What is a Dry Bag? Everything You Need to Know Before You Buy
Ryan Hotchkiss February 27th, 2026 Posted In: Articles
If you love water sports, you already know the struggle: everything gets wet. Your towel. Cell phone. Your car seats. Change of clothes. That one dry hoodie you were counting on after a chilly session? Soaked.
That’s exactly why the dry bag might be one of the greatest inventions in watersports history.
But what is a dry bag, really? And how do you choose the right one for your adventures — whether you’re surfing, kayaking, diving, rafting, or learning to SUP? Let’s break it all down below!
What Is a Dry Bag?
At its simplest, a dry bag is a waterproof storage bag designed to keep water out, or keep water in.
Most dry bags are made from durable materials like PVC, coated nylon, or rubberized fabrics. Nylon versions use an internal laminate layer that prevents water from seeping through the weave of the fabric.
The classic design is beautifully simple: You fold the top edges together, roll them down tightly several times, and clip the side buckles together. That roll-top seal creates a watertight closure.
It’s flexible. It’s durable. And when sealed properly, it’s highly water-resistant — often waterproof.
Whether you’re rafting down a river, paddling out on your SUP, or stashing gear on a dive boat, a dry bag protects your essentials from splashes, spray, rain, and accidental dunks.
The Science of Waterproofing: Understanding IP Ratings
One of the most common follow-up questions after “what is a dry bag?” is: “Can I submerge it?”
That depends on the IP rating. IP stands for (no, not the computer IP you’re probably thinking of) Ingress Protection. It’s a standardized rating system that measures how resistant something is to dust and water.
Here’s what matters for dry bags:
- IPX6: Protected against heavy splashing, rain, and strong spray. This is where most roll-top dry bags fall.
- IPX8: Fully submersible under specific conditions. Typically applies to bags with waterproof zippers and reinforced seals.
Important note: Most traditional roll-top dry bags are not designed for prolonged submersion. If forced underwater long enough, water can eventually push through the folds of the roll-top seal.
For kayaking, surfing, boating, and beach use? Roll-top bags are perfect. For diving or repeated full submersion? Look for higher IP-rated waterproof systems.
Dry Bag vs. Dry Sack: Is There a Difference?
You’ll often hear people use the terms interchangeably, but there’s a subtle difference when discussing Dry bag vs. dry sack.
- Dry Sack: Typically refers to lightweight roll-top bags used for organizing gear inside larger packs (popular in camping and backpacking).
- Dry Bag: Usually implies a more rugged, heavy-duty waterproof bag designed for marine or watersport environments.
In practical terms? Most watersport customers are looking for a dry bag. They need something durable enough to handle sand, saltwater, boat decks, and being tossed into truck beds.
Dry Bag vs. Dry Backpack: Which One Do You Need?
The market has evolved beyond the classic “sandwich bag” style cylinder. Now, one of the biggest buying decisions customers face is: Traditional roll-top dry bag… or dry backpack?
Here’s how to think about it:
Traditional Roll-Top Dry Bag
Best for vessel-powered transport
- Cylindrical shape
- Extremely durable
- Easy to stuff into boat hatches or cargo areas
- Often floats if air is left inside
- Great for kayaking, rafting, and boat diving
If your gear mostly rides in a boat, this is your go-to.
Dry Backpack
Best for human-powered transport
- Padded shoulder straps
- More ergonomic for hiking to surf breaks
- Great for SUP access points or cliffside dive entries
- Often includes extra compartments
If you’re walking any real distance with your gear, a dry backpack will save your shoulders.
What Size Dry Bag Do I Need?
This is easily the #1 question shoppers ask.
Here’s a simple size breakdown:
- 5L – 10L: Perfect for small essentials — phone, keys, wallet, snacks, sunscreen.
- 20L (The Sweet Spot): Fits a towel, change of clothes, and light jacket. Great for day paddling or beach sessions.
- 30L – 40L: Ideal for bulky gear. Large enough for a full wetsuit (even up to 5mm thick), wetsuit boots, and neoprene gloves.
- 60L+: Expedition-sized. Perfect for multi-day rafting, dive travel, or camping trips.
For surfers and divers specifically, 30L+ is usually the magic number.
How to Use a Dry Bag for Wet Wetsuits
Here’s where dry bags become a total game-changer.
Most people think dry bags are just for keeping things dry. But one of the best uses? Keeping your car dry. After a cold surf or dive session, your wetsuit is heavy, soaked, and dripping saltwater everywhere. Tossing it into your trunk without protection is a recipe for mildew, odor, and salt damage.
Here’s how to use a dry bag for wet wetsuits:
- Choose a 30L–40L bag (minimum for full suits).
- Roll your wetsuit tightly to reduce trapped air.
- Place boots and gloves inside the suit roll.
- Seal the bag securely.
- Transport home without worrying about leaks.
It protects your vehicle and contains the mess until you can properly rinse and wash your wetsuit.
(And once you’re home, make sure you’re following proper care steps — see our full guide on How to Clean a Wetsuit to keep your neoprene in top condition.)
Why Not Just Use a Trash Bag or a Hard Case?
Sure, you could use a plastic trash bag. Until it tears. And they always tear.
Hard waterproof cases (like Pelican-style boxes) are fantastic for electronics — but they’re bulky and rigid. They don’t compress or conform to boat hatches. They bang around in cargo areas.
Dry bags are flexible, tough, lightweight, and packable. That’s what makes them irreplaceable in water sports.
Frequently Asked Questions
Can dry bags float?
Yes — if you leave some air inside when sealing them. The trapped air provides buoyancy. Just don’t rely on flotation as a substitute for a PFD.
How do I clean a dry bag?
Rinse with fresh water after saltwater use. For deeper cleaning, use mild soap and water. Let it air dry completely — ideally inside-out — to prevent mold or odor buildup.
Can I store wet gear in a dry bag long term?
No. Dry bags are for transport, not long-term storage. Always remove wet gear and allow it to dry properly as soon as possible!
Final Thoughts: A Small Investment That Solves Big Problems
If you spend time on rivers, lakes, or in the ocean, a dry bag isn’t a luxury — it’s essential gear.
Whether you’re a surfer protecting your car from a dripping 4/3mm, a diver keeping clothes dry on a boat, a paddler stashing snacks and electronics, or a triathlete transporting race gear, understanding what is a dry bag, and choosing the right one, makes your entire experience smoother.
The right size, style, and the right waterproof rating. It’s one of the simplest upgrades you can make… and one you’ll wish you had sooner!
