Waterproof Backpack: Buying Guide

Dry Bag backpacks come in a wide range of shapes, sizes and levels of waterproofness. There are almost 101 options to consider, so we wrote this article to walk you through all the features and help you select the perfect waterproof rucksack for your needs.

Size

Waterproof backpacks are measured in the volume of kit they can carry. The start at 20 liters. This is the size of a regular day pack or school bag. We call it the Goldilocks size, not too big and not too small. You can pack everything you need to a day out, without making it too heavy to carry. For cycling, we’d recommend 20 litres. If you’re hiking 30 – 40 litres is more than ample. Extended overnight adventures will likely need 45 litres and upwards.

OverBoard’s range of backpacks come in 20, 30 and 45 litres, you can also get a 60 litre backpack / dry tube hybrid (more on this later).

Watershed do the 20 litre Big Creek, the 40 litre Animas and the giant 65 litre Westwater. 

Exped’s Cloudburst 25 is (yes you guessed it!) 25 litres and despite being mega lightweight, is foul weatherproof and even floats as demoed here: Note, we wouldn’t fully submerse it, but you can’t fault the plucky little bag. There is minimal padding in the straps, but they’re comfortable to wear all day. The bag has a handy waist strap to keep it steady if you’re cycling or hiking.

 Swim Secure have a really nifty Wild Swim backpack that doubles as a floating dry bag that can hold your clothes, towel and shoes. No more leaving them on the bank when you take a dip! You then detach the shoulder straps and put them in the bag along with your clothes, roll down the top to the line marked on the outer, secure it with the buckles and then inflate by blowing into the valves. The floating dry bag is then attached to the swimmer via a waist strap and it floats behind them, making them highly visible to other water users and those on the bank.

Waterproofness & materials

Just how waterproof a bag proves to be is down to two factors: the material it’s made from and the method of sealing it (more on this later). 

There are official waterproof ratings, known as Ingress Protection (IP). Overboard have had all their bags tested and rated and we’ve used these to benchmark the other brands we stock too.

IP65 is foul weatherproof. It will keep the rain out and water will bead up and run off, but it’s not strictly submersible. These bags are generally made from a lighter weight material. They’re more pliable, so ideal for packing inside bigger, more waterproof bags.

IP66 means the bag is 100% waterproof and even briefly submersible.

When we say briefly submersible we mean it! The material they’re made from is a thick tarpaulin. Very heard wearing and can be hauled over rocks, on and off boats, etc. However the method of sealing is to roll the top down three or four times and secure with a buckle. Under testing, we saw that some air bubbles escape through the rolled top. This isn’t an issue if you submerge the bag briefly, but there may be a trickle of water in there if the bag is held under for a prolonged period of time. It is worth noting that most bags will naturally float with their tops up out of the water. If you’re carrying valuables, such as a phone, it is worth putting these in an IP68 rated case.

IP68 is the Rolls-Royce of waterproofness! These bags are 100% waterproof when submerged to a depth of 6 meters for 60 minutes (such as the OverBoard phone cases), whilst the amazing Watershed range of bags are rated to a staggering depth of 91 meters / 300feet where the water pressure actually helps keep the zip-lock style seal closed.

Materials and construction

The actual material a bag is made from is key. Lightweight bags like the Cloudburst 25 are made from 70 D taffeta nylon, and PU coated with a DWR (Durable Water Repellent) film that causes water to simply bead up and roll off. This does wear off with time and can be replaced by products like Nickwax.

Lightweight bags are more pliable and they tend to sit at a lower price point. The material is generally stitched together and the seams taped to ensure they are watertight.

Mid-weight bags like Overboard’s Classic range (Backpacks, Duffels and Panniers) are made from a hardwearing tarpaulin material and the various panels are welded together using Radio Frequency (RF) – to effectively make one complete leak proof piece of material.

OverBoard's Pro-Sports range of bags not only have many more features than the Classics, such as; external mesh pockets, bungee cord, chest and waist straps, they're also made from a thicker, more hard wearing material. As a result the weigh a little more too.

The Pro-Light bags are packed with all the same features as above and have a handy drinks bladder pocket against the back pad. They are also made from a lighter weight material - available in black only. 

The more premium Watershed bags are made from a polyurethane-coated nylon fabric and then RF welded for 100% waterproofness. They’re both pliable and durable. And, whilst they have a price tag to match, they will serve you well for many years. The Watershed bags have really top quality webbing straps, carry handles and gear loops, so they can be safely lashed to white water rafts, the roof racks of expedition vehicles or the nose of your paddle-board. 

Sealing

As covered above, many of the waterproof backpacks have a a roll-top seal. You typically pinch the top together, roll tightly three to four times (or more) and secure with a buckle. This forms a quality seal that can withstand a brief submersion. We recommend you check you’ve got a good seal on the bag by testing it in the bath before you head off on a really wet adventure.

OverBoard’s excellent phone cases (available in small and large sizes) use a mechanical clip to make them watertight. Simply slide the clips together to make the seal. When we tested these we did see some bubbles coming out, but these are from air trapped in the plastic top, and not from ingress into the case.

Watershed use a Zip-Lock style seal that runs the full width of their duffel bags and backpacks. There is a technique to opening them, that gets easier as you practise. Slide your thumbs through the two loops, put your hands tighter palm to palm and kink the seal into an S shape. Then pull gently apart. 

To close you simply pinch the seal shut and run your hand across the full width the to ensure it’s all snapped together and watertight. Roll the top down (for neatness and to protect the seal from debris) and secure with the buckle.

Note. You have to keep the seal lubricated. There is a sachet of lube with the bag, and if you’re out on an expedition, you can use saliva.

Accessories

All waterproof backpacks could benefit from more pockets. Fact. All OverBoard rucksacks have a nifty strip of velcro on the inside which this handy laptop-tidy fixes to. Available in two sizes to fit 14 or 15 inch laptops. There are handy packets for notebook, charging cables, pen and keys. The lap-top tidy is easy to remove at airport checks, etc. making your waterproof rucksack a versatile travel bag. 

Dry Tube / Backpack hybrid 

Looking for big volume and a versatile bag? The MASSIVE 60 litre dry tube / backpack hybrid could be just the ticket. The monster dry tube has a surprisingly comfortable, removable, harness system. So you can load it up with kit, strap it on and hike. We use it for storing all our kayaking kit. It's great for carrying all the wet kit home at the end of a paddle avoids soggy puddles in the car.