Sea to Summit Ultra-Sil Dry Daypack Packable Backpack Review
An affordable, water-resistant packable backpack for travel and day hikes
October 22nd, 2026
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Our verdict
The Sea to Summit Ultra-Sil Dry Daypack is an affordable packable travel daypack that works as a functional backup bag without taking up too much room. It packs compactly into a very small Ultra-Sil stuff sack that includes a handy aluminium carabiner to clip onto your primary bag, purse, sling, or larger backpack. It is designed for travelers who want a lightweight stuff sack rather than a structured daypack or backpack.
We tested the Sea to Summit Ultra-Sil Dry Daypack on a week-long trip to Germany that involved city tours, casual hiking, and a short run. We even used it for three months on weekend trips to Chicago, taking it to farmers markets, on bike rides, and on errands around town.
It has one main compartment that can hold items like jackets, caps, snacks, and knick-knacks. The bag performed flawlessly in terms of durability and comfort for carrying for short periods of time as well as a 5-mile hike. It is easy to open with a roll-top closure and pack away when not in use. The bungy cords on the front are convenient to store quick-access items like a rain jacket or a hat.
Sea to Summit Ultra-Sil Dry Daypack
The biggest limitation of this daypack is that it does not have side water bottle pockets, and the straps can dig in when loaded to its full capacity of 22 liters. It’s also not fully waterproof, as it can’t be submerged and failed our shower test (simulating a downpour).
We recommend the Sea to Summit Ultra-Sil Dry Daypack for people who want to travel light or don’t have much space to pack a regular daypack. It is also best for light loads like a jacket and a small bottle instead of heavy gear, like cameras.
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Sea to Summit Ultra-Sil Dry Daypack specifications
Price: $70
Capacity: 22 L
Empty weight: 3.9 oz
Packs into own pocket: Yes, attached Ultra-Sil stuff sack with a small aluminum carabiner
Fabric: 30D Ultra-Sil siliconized high-tenacity CORDURA nylon; hydrostatic head greater than 2,000 mm
Water resistant: Yes, seams are tape-sealed
Waterproof: Yes (although in testing, dampness did develop inside during our shower test)
Laptop sleeve: No
Water bottle pockets: No
Sternum strap: No
Hip belt: No
Back panel: No padding or structure
Shoulder straps: Reinforced, adjustable straps designed to resist bunching
Carry-on compliant: Yes, can even clip to a purse or backpack with provided carabiner
Comparison table
| PACKABLE BACKPACK | CAPACITY | WEIGHT | BOTTLE POCKETS | WATER RESIST | CARRY ON | MSRP |
|---|---|---|---|---|---|---|
| Sea to Summit Ultra-Sil Dry Daypack | 22 L | 3.9 oz | ❌ | ✅ | ✅ | $70 |
| Osprey Daylite | 13 L | 19.8 oz | ✅ | ✅ | ✅ | $70 |
| Arc'teryx Heliad 15 | 15 L | 7.1 oz | ❌ | ✅ | ✅ | $80 |
| Matador 18L Packable Backpack | 18 L | 9.0 oz | ✅ | ✅ | ✅ | $75 |
Best for
Short day trips and as a day pack to use at base camp
Day hikes where you don’t need to carry too much water
City exploration, errands, or short sightseeing excursions
A packable option for outdoor adventures like biking or walking
What we liked
Roll-top design lets you pack the bag fuller or roll it down for smaller loads
The bungy cords can hold items like jackets or a cap for easy access without opening the bag
The stuff sack can be clipped onto a larger travel bag or purse with the carabiner that is provided with the bag
What could be better
The shoulder straps are not padded, so the pack is better suited to comfortably carry lighter loads
There is no hip strap for comfortable carry for long periods of time
Not fully waterproof in a heavy downpour
Some colors, like High Rise, are semi-transparent so contents are visible
There are no external zippers or external water bottle holders
How we tested
We tested the Sea to Summit Ultra-Sil Dry Daypack on a week-long trip to Germany that involved city tours, casual hiking, and a short run. We even used it for three months during the summer on weekend trips to Chicago, taking it to farmers markets, on bike rides, and on errands around town.
We wore it on full travel days carrying a typical load of essentials like a jacket, water bottle, snacks, wallet, and cap. We carried a DSLR camera and lens on a short run in Berlin.
We tested how easily it packed and unpacked, size and weight when full and partially loaded, as well as comfortable carry at different loads. We also tested it in the shower to assess the waterproof fabric and how well it protected the contents. After repeated use, we also evaluated the fabric, roll-top clips, straps, seams, and overall structure for signs of wear and durability.
Additionally, we tested this pack alongside others in our Best Packable Backpacks guide.
Performance in the field
Packability
The Sea to Summit Ultra-Sil Dry Daypack is a packable backpack that fits into a small attached stuff sack. The stuff sack has a carabiner so it can be clipped to a larger backpack or a purse when not in use.
Deployment and usability
Because the Sea to Summit Ultra-Sil Dry Daypack packs into an attached stuff sack, it needs to be unpacked before it can be deployed. We carried it in our carry-on luggage and used it when we reached our destination in Germany. We also took it on day hikes and city trips to Chicago. On a bike ride in Chicago, we clipped it to a jacket and used it to store our helmet while running errands. The packed size is smaller than a typical phone so it is extremely portable for just-in-case situations too.
Carry comfort
We wore it for several hours at a time with different loads of 10 lb, 15 lb, and 22 lb. We felt the pack carried each load very well considering the shoulder straps lack padding. But at the heaviest load, the shoulder straps did start to bunch and the bag sagged, making it uncomfortable for extended carry. We also used it on day hikes in addition to everyday travel.
Load handling
We tested the Sea to Summit Ultra-Sil Dry Daypack at partial and full capacity and found the shoulder straps to bunch at higher loads when used for the whole day. However, the straps were comfortable at half loads, and the bag still felt secure at full capacity. Because it doesn’t have a rigid structure, it can fit odd-shaped items like a camera and a helmet.
Durability
After repeated use over several months, the Sea to Summit Ultra-Sil Dry Daypack showed no signs of fabric wear, including abrasion, fraying, and changes in the material’s structure. The clips along the roll top were also reliable after repeated opening and closing, and the shoulder straps did not fray or snap.
Water resistance
The Sea to Summit Ultra-Sil Dry Daypack is marketed as a waterproof pack. We tested the Sea to Summit Ultra-Sil Dry Daypack in both light rain and more sustained wet conditions under the shower to see how well it protects the contents in real-world use. The fabric provided enough protection to keep everyday essentials dry. But under the shower, we noticed some moisture inside the bag, and the interior panel was damp to the touch.
The pack material is waterproof, but the pack is not meant to be submerged. During our shower test to simulate a downpour, we noticed some dampness inside the bag, so we would not consider this daypack waterproof.
Organization and pockets
We tested the Ultra-Sil Dry Daypack with the things we actually carry while traveling, including a phone, wallet, keys, snacks, and a water bottle. Because there are no internal organization pockets, all the contents are packed together and need a little rummaging to find specific items.
Features
It is made of Ultra-Sil 30D siliconized high-tenacity CORDURA nylon fabric and carried up to 22 lb in our testing, though loads of 15 lb or less are better suited to extended carry for comfort
It has reinforced shoulder straps that are comfortable under load
It packs into an attached CORDURA fabric Ultra-Sil stuff sack that includes a handy aluminium carabiner
All seams are tape-sealed to keep contents dry, but the pack is not intended for submersion
It has an elastic compression lacing system on the exterior
Warranty: Limited lifetime warranty for the life of the product under normal use
Sustainability
Sea to Summit is a Certified B Corporation that puts sustainability at the center of its gear, focusing on durable, repairable products and using recycled materials wherever possible. Learn more about Sea to Summit’s sustainability commitments on their website.
Similar packable backpacks
Sea to Summit Ultra-Sil Dry Daypack vs. Osprey Daylite
Price: $70
Capacity: 13 L
Empty weight: 19.8 oz
Water resistant: Yes
Bottle pocket: Yes
The Osprey Daylite is a structured daypack with a ventilated back panel and padded shoulder straps. It has plenty of pockets and zippered compartments to store travel essentials. The Sea to Summit Ultra-Sil Dry Daypack, on the other hand, is an unstructured bag that packs into a tiny stuff sack and works as a backup bag or summit sack. These are two very different bags.
Choose the Sea to Summit Ultra-Sil Dry Daypack if you want a lightweight bag for errands or as a backup bag while traveling. Choose the Osprey Daylite if you value comfort, durability, and pockets in an everyday travel bag or hiking daypack.
Read our full Osprey Daylite review for more on its carry comfort and organization.
Osprey Daylite Pack
Sea to Summit Ultra-Sil Dry Daypack vs. Arc’teryx Heliad 15
Price: $80
Capacity: 15 L
Empty weight: 7.1 oz
Water resistant: Yes
Bottle pocket: No
Both the Sea to Summit Ultra-Sil Dry Daypack and the Arc’teryx Heliad 15 are unstructured bags that pack away for convenient carry or stash in a suitcase or larger backpack. The Heliad has mesh shoulder straps and a zippered outside pocket.
Choose the Sea to Summit Ultra-Sil Dry Daypack if you want a bag to carry essentials like extra layers or snacks, as it does not have any external or internal pockets. The Arc’teryx Heliad has a zippered external pocket (while the Sea to Summit Ultra-Sil has none), so it can be used for more organized ultralight travel.
Arc’teryx Heliad 15
Sea to Summit Ultra-Sil Dry Daypack vs. Matador 18L Packable Backpack
Price: $75
Capacity: 18 L
Empty weight: 9.0 oz
Water resistant: Yes
Bottle pocket: Yes
The Sea to Summit Ultra-Sil Dry Daypack and the Matador 18L Packable Backpack are both unstructured bags that pack small and work as a backup bag or summit sack. The Matador has a capacity of 18 liters, whereas the Sea to Summit has a capacity of 22 liters. The Matador also has expandable external mesh pockets to carry water bottles, which the Ultra-Sil does not have. It’s also available in a waterproof version.
Choose the Sea to Summit for light travel and short day trips, and choose the Matador Packable Backpack as a summit bag or for longer travel days, as it has some organizational pockets and external water bottle pockets.
Matador 18L Packable Backpack
Should you buy the Sea to Summit Ultra-Sil Dry Daypack?
Buy if:
You prioritize an unstructured packable backpack
You want some waterproof capabilities in your backpack
You want a roll-top design with a larger capacity
Skip if:
You want a backpack that is structured
You want padded straps and a ventilated back panel
You want internal pockets for organizing items
You want external water bottle pockets
For more supportive options, see our guide to the best daypacks for hiking.
FAQ
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It is marketed as a waterproof pack. The material is meant to be waterproof and the seals are tape-sealed.
That being said, we found dampness inside the Ultra-Sil Dry Daypack during the shower test, so we would not rely on it to keep gear dry in a downpour.
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We tested the Ultra-Sil Dr Daypack by wearing it for several hours at a time with loads of 10 lb, 15 lb, and 22 lb. While the fabric held up at 22 lb, we found that the shoulder straps bunched at higher loads. We recommend it for lighter loads of up to 15 lb and shorter outings if above 15 lb.
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No. We carried a water bottle inside the main compartment.
Where to buy the Sea to Summit Ultra-Sil Dry Daypack
The Sea to Summit Ultra-Sil Dry Daypack is popular, so you have options when it comes to retailers. Here are some of the pros of the retailers.
Sea to Summit
Pros: Free U.S. shipping on orders over $50; easy 60-day returns; limited lifetime warranty against manufacturing defects.
Amazon
Pros: Free 2-day shipping with Amazon Prime membership (can be same-day delivery in major metropolitan cities)
DICK’S Sporting Goods
Pros: This major sporting goods retailer is starting to sell more specialized outdoor gear. You can get free store pickup and some locations have same-day delivery. It also offers free shipping over $49 for ScoreCard members.
Advice on where to buy
In general for gear, we recommend purchasing from a place with easy or free returns when possible.
Why you should trust us / About the author
The author, Karthika Gupta, is an adventure travel writer with over 25 years of adventure travel experience. She has hiked on all seven continents and loved every minute of it. She has even completed Highlander UAE and Fjallraven Classic Chile, along with hundreds of miles in the Indian Himalayas. She covers outdoor gear, small-group adventure travel, and hiking/camping trends for national and international publications, blending real experience with practical advice. Her work is grounded in miles hiked, boots tested, and a belief that everyone belongs in the outdoors regardless of gear and experience—you don’t need to overpack or overcomplicate to have a meaningful adventure.
You can find more of her work on her Treeline Review author page.
You can find more of her adventures on her Instagram @karthikagupta or her website.
