Waterproof Bags (Dry Bags) Explained: How to Choose

A waterproof bag keeps its contents dry when the outside gets wet — from a rain shower on a hike to a wave over the side of a boat. In practice, most people searching for a "waterproof bag" want what outdoor shops call a dry bag: a bag with a roll-top closure that you fold down and clip shut. The two terms mostly mean the same thing.

This guide explains how these bags work, what separates a good one from a bad one, and how to pick the right size and style for how you actually use it — whether that's the beach, a hike, a boat trip or a motorcycle.

How a waterproof bag actually keeps water out

Three things decide whether a bag is genuinely waterproof: the fabric, the seams and the closure. A bag is only as waterproof as its weakest point, and that is almost never the fabric.

The three closure types

• Roll-top (dry bag). You fold the open end over on itself several times and clip the ends together. No zip, no teeth, nothing to leak — the folds create a long, tight barrier. This is the most reliable closure for rain, spray and brief dunks, and the one we recommend. See how to close a roll-top bag properly.
• Waterproof zip. A sealed, rubberised zip. It's quick to open and good for things you reach into often, but it is the first part to wear out, and it needs to be kept clean and lubricated.
• Standard zip with a water-resistant coating. Fine for drizzle. Not something to trust with a phone in a downpour — see waterproof vs water-resistant.

Seams and materials

Needle holes are tiny doorways for water, so stitched seams are the classic weak point. Better waterproof bags use welded or taped seams: the panels are fused together with heat or covered with waterproof tape, so there are no stitch holes at all. The fabric itself is usually a coated or laminated material — common choices are PVC-coated fabric, TPU-laminated fabric and coated nylon or polyester. Each trades off weight, toughness and cost; a thicker material resists scuffs and sun better, a thinner one packs smaller.

Which size do you need?

Dry-bag sizes are quoted in litres. As a rough guide: 5 litres holds a phone, wallet, keys and a small first-aid kit; 10–15 litres holds a change of clothes or a jacket; 20 litres and up is for overnight gear. Remember that you lose some usable volume when you roll the top down. Our full size guide for 5L vs 15L bags goes into detail.

Features worth paying for

• A detachable shoulder strap — turns the bag into a waterproof shoulder bag. More in our waterproof shoulder bag guide.
• D-rings or attachment points — to clip the bag to a kayak, boat or backpack, or to strap it to a motorcycle.
• A reinforced base — stops the bag wearing through where it touches rocks, decks and wet ground.
• A buckle you can use one-handed — wet, cold hands are clumsy.
• Honest instructions — a seller who tells you how many times to roll the top is a seller who tests their product.

Where the Rihla bags fit

Rihla makes two roll-top waterproof bags: the 5L in black for day essentials and the 15L in olive for overnight loads. Both have a buckle-clip roll-top closure, a reinforced base and a detachable shoulder sling with dual buckles. They're built around Lebanon's use cases — the coast, the mountains and the road — and you pay on delivery, anywhere in the country.