Sea to Summit
Sea to Summit Ultra-Sil Dry Bag (8 L)
- Waterproof build: 6/10 How well its build keeps water out, from the published seams, closure and submersion claim.
- Weight for its size: 8/10 How much it adds to your pack for the space it protects.
Protecting a down jacket, spare clothes or a food bag inside a rucksack
- Capacity
- 8 L
- Weight
- 39 g
- Seams
- Taped
- Closure
- Roll top
- Fabric
- 30 denier
Where to buy
Sea to Summit £21 In stock. Delivery £4.50. 8 L in stock in every colour. Free delivery over £75.
View at shop: Sea to SummitPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Waterproof build
From maker's figures 6/10How well its build keeps water out, from the published seams, closure and submersion claim. 6: A bit better than average.
Taped seams and a hypalon roll-top. Sea to Summit says it is waterproof where the bag will not be submerged and not for paddle sports, so there is no submersion claim: the 3 band. The hydrostatic head (above 2,000 mm) is a fact, not a score.
Weight for its size
From maker's figures 8/10How much it adds to your pack for the space it protects. 8: Clearly better than most.
39 g for 8 L is 4.9 g/L, in the 4.0–5.9 g/L band (Sea to Summit's figure; Ultralight Outdoor Gear lists 38 g, the same band).
What reviewers say (out of 10)
Ratings marked * are from reviews and are not part of the trip score. They are reviewers' scores, not our own measurements. How we score
Durability*
Reviewers' average 7/10How well the fabric and seams resist scuffs and holes.
3 reviews on durability, e.g. "The Ultra-Sil is still very tough for the weight and will hold up for years if you avoid sharp edges and rough surfaces.".
Reviewers disagree on this.
Ease of use*
Reviewers' average 8/10How easily it closes, seals and packs.
5 reviews on ease of use, e.g. "With the excess air forced out, the sides of these bags’ openings simply close and seal.".
In short
Good for
- Protecting a down jacket, spare clothes or a food bag inside a rucksack
- Ultralight kits where every gram counts: 39 g for 8 L
- Use inside a pack, not strapped outside or for paddling
Strengths
- Very light: 39 g for 8 L (4.9 g/L)
- Translucent 30D Ultra-Sil fabric with Cordura yarns, so you can see what is inside
- Slippery finish for easy packing and unpacking
- Taped seams and a hypalon roll-top closure
- Oval base stops it rolling away
Weaknesses
- Thin 30D fabric, meant for inside a pack rather than rough outside use
- Not submersible: Sea to Summit says it is not for paddle sports
- No independent tests of the 8 L itself were found, so durability and ease scores are missing
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (7)
- Sea to Summit UK: Ultra-Sil Dry Bag, 8 L size table
- Backcountry Magazine: Sea to Summit to Stuff Sack: Packing Systems Reviewed (Ultra-Sil Dry Bag, 5 L and 8 L used)
- Vertical Life: Sea to Summit Dry Bags, Reliable Protection for Wet Adventures (Ultra-Sil Dry Bag Set 3, 5 and 8 L, with two other Sea to Summit ranges)
- Travel + Leisure: The Best Dry Bags, Tested and Reviewed (Best Set: Sea to Summit Ultra-Sil Dry Bag set of 3, 5 and 8 L, owned for over a year)
- OutdoorGearLab: The Best Dry Bags (Sea to Summit Ultra-Sil Set of 3, 3, 5 and 8 L, one of 18 bags tested)
- CleverHiker: Best Stuff Sacks of 2026 (Sea to Summit Ultra-Sil Dry Bag, 39 g for 8 L, 'Best Waterproof Stuff Sack')
- The Good Ride: Sea To Summit Ultra Sil Dry Bag review by Steph (13 L and 8 L tested)