Dry Bags Explained: PVC vs TPU vs Coated Polyester Dry Bags

Dry bags are essential waterproof storage solutions for kayaking, rafting, hiking, camping, and marine activities. Whether you’re navigating whitewater rapids or hiking in heavy rain, choosing the right dry bag material can make the difference between dry gear and damaged equipment.

This guide explains what dry bags are, the different types of dry bags, and how PVC, TPU laminate, and coated polyester/nylon dry bags compare in durability, weight, and performance.

What Is a Dry Bag?

A dry bag is a waterproof bag designed to protect gear from rain, splashes, and short periods of submersion. Most dry bags use a roll-top closure or waterproof zipper, combined with welded or taped seams, to create a watertight seal.

Dry bags are commonly used for:

• Kayaking, canoeing, rafting, and paddleboarding
• Hiking and backpacking in wet climates
• Camping and expedition travel
• Marine and coastal activities

Unlike backpacks, dry bags focus on waterproof protection rather than internal structure or organization.

20-Litre Waterproof Dry Bag Backpacks with Comfort Shoulder Straps

These lightweight, stylish, waterproof backpacks are perfect for everyday protection made with sturdy PVC they are beach and adventure ready.  Features the 30 Litre too. 

Dry Bag Materials Explained

The material of a dry bag directly affects its waterproofing, durability, weight, and lifespan.

PVC Dry Bags

PVC (polyvinyl chloride) dry bags are thick, rugged, and highly abrasion resistant. They are commonly used in whitewater and expedition settings.

Advantages:

• Excellent waterproofing
• Very durable and puncture-resistant
• Affordable and widely available

Disadvantages:

• Heavier than other materials
• Can become stiff in cold temperatures
• Higher environmental impact

Best for: Whitewater rafting, rugged environments, heavy use

TPU Laminate Dry Bags

TPU laminate dry bags combine a nylon fabric base with a TPU waterproof coating, offering an excellent balance of strength and flexibility.

Advantages:

• Lighter than PVC
• Flexible in cold weather
• Durable and long-lasting
• More environmentally friendly than PVC

Disadvantages:

• Higher cost than PVC
• Moderate UV sensitivity over time

Best for: Kayaking, backpacking, cold climates, frequent outdoor use

Coated Polyester / Nylon Dry Bags

These dry bags use lightweight woven fabrics coated with polyurethane or silicone to provide water resistance.

Advantages:

• Very lightweight
• Highly compressible and packable
• Comfortable for long hikes

Disadvantages:

• Lower abrasion resistance
• Not ideal for full submersion
• Shorter lifespan under heavy use

Best for: Hiking, travel, rain protection inside backpacks

PVC vs TPU vs Coated Polyester Dry Bags Comparison

Feature	PVC Dry Bags	TPU Laminate Dry Bags	Coated Polyester / Nylon Dry Bags
Waterproofing	Excellent when sealed	Excellent and reliable	Good, limited under submersion
Durability	High – very rugged	High – strong and flexible	Moderate
Weight	Heavy	Moderate	Lightest
Packability	Compressible	Compressible	Highly compressible
Lifespan	Long with care	Very good long-term	Shorter lifespan
Seam Construction	Welded seams	Welded seams	Often taped seams
UV Resistance	Moderate	Moderate	Low
Best Use	Whitewater, harsh conditions	Most outdoor activities	Backpacking, light rain

How to Choose the Right Dry Bag

When choosing a dry bag, consider:

• Activity type: Whitewater and marine use require PVC or TPU
• Weight needs: Backpackers benefit from TPU or coated fabrics
• Durability requirements: Frequent or harsh use favours PVC or TPU
• Capacity:
• 5–10 L for electronics
• 20–30 L for day trips
• 40–60 L for multi-day trips

Conclusion

Dry bags come in a range of styles and materials, each suited to different conditions.

• PVC dry bags offer maximum durability at a lower cost
• TPU laminate dry bags provide an all-around performance
• Coated polyester/nylon dry bags prioritize lightweight portability

Understanding these differences ensures you choose the right waterproof dry bag to keep your gear protected in any environment.

Salty Kit bags are made with sturdy 500D PVC tarpaulin with roll top and waterproof heat welded seams, making them super tough - the ideal bag for every adventure. 

Featuring our rugged 30 litre dry bags, one big compartment which is great for larger items and a great deck bag shape for paddleboarding.

FAQs: Waterproof Sacks vs Dry Bags

What is the difference between a waterproof bag and a dry bag?

A waterproof bag resists rain and splashes but may not be airtight or fully submersible. A dry bag is designed to be completely waterproof and often floats when properly sealed.

Can dry bags be fully submerged?

Check your IPX rating for this question.  

• IPX6: Pressure-tested against strong currents and surface chop
• IPX7: Handles short descents up to 1 meter, like reef diving
• IPX8: Certified for deep diving conditions and extended submersion

Our dry bags are IPX66 tested and will survive waves and a dunking when sealed correctly using the roll-top method.  Its a good idea to keep valuables in an IPX8 container inside for further protection.  Our bags are ideal for water sports, camping, and river crossings.

“A good waterproof bag protects your gear. A great one protects your day.” — Salty Kit