TL;DR: After testing in creek crossings and monsoon commutes, the Sea To Summit Sprint 20L is my pick for a truly waterproof travel backpack. Roll-top closure, tape-sealed seams, and 420D reinforced bottom—it kept everything bone dry even under direct water flow.
I learned about waterproof backpacks the hard way—halfway through a creek crossing in summer, I looked back and found my pack had already taken on water. Wet gear in the outdoors is miserable. Some people wrap their stuff in plastic bags, but those tear easily, don't seal well, and aren't exactly eco-friendly.
After ruining a few trips this way, I started looking for a proper waterproof pack. That's when I found Sea To Summit.
Why Sea To Summit?
This is actually my third Sea To Summit waterproof pack. The brand has built a solid reputation in the ultralight outdoor space—reliable performance and a certain aesthetic that outdoor enthusiasts appreciate. My previous Sea To Summit packs have been with me through some memorable adventures, so when summer rolled around and I had some water-heavy routes planned, I grabbed the Sprint 20L without hesitation.
And here's the thing—I don't just use it for outdoor trips. I bring it traveling too. Rainy days, airport transfers, city commutes during monsoon season—the waterproofing comes in handy more often than you'd think.
Note: I bought an earlier version—the current model has a slightly different look, but the core design and waterproofing tech remain the same.
Specs
- Capacity: 20L (roll fewer times for extra space)
- Dimensions: 61cm × 36cm when laid flat
- Main fabric: 210D nylon
- Bottom fabric: 420D nylon (reinforced for abrasion)
- Colorway: Blue and black—simple but visible on the trail
Design Details
The roll-top closure works like a classic dry bag—fold it down, clip it shut. There's a pressure strip along the fold and reinforced stitching at stress points. All interior seams are tape-sealed, and the white inner lining makes it easy to spot your gear when digging around inside.
There's also a small zippered pocket inside the main compartment—not huge, but handy for keeping important items separate.
The back panel is full mesh padding—soft against your body and breathable. There's a slight channel down the center that keeps the pack off your spine, which helps with airflow. The S-curved shoulder straps follow your body's contour, and they're perforated for ventilation. After adjusting the fit, the pack sits stable and comfortable even on rough terrain.
The padding also has decent moisture-wicking properties—after a sweaty hike, it doesn't stay damp for long.
The reinforced 420D bottom is built to handle rough surfaces.
The external bungee cord is handy for strapping on a rain jacket or compressing the pack when it's not full.
Waterproof Test
I put this pack through a real test—placed it directly under flowing creek water, roll-top facing the stream. Wedged a branch over the straps so it wouldn't wash away. After a solid soak, the inside was still bone dry.
Water beaded up and rolled right off. The reinforced 420D bottom held up against the rocks without any signs of wear.
Why It Works for Travel
Most "waterproof" backpacks are designed for hardcore outdoor use—they look out of place in airports or city streets. The Sprint strikes a balance. It's understated enough for urban environments but tough enough for real conditions.
I've used it for:
- Creek crossings and kayaking trips
- Rainy commutes during monsoon season
- Airport transfers in unpredictable weather
- Day hikes where weather can turn quickly
The 20L capacity is enough for a day's worth of gear or a light overnight trip. Not huge, but that's the point—it's meant to be versatile, not a full expedition pack.
Update: The Sprint 20L has been discontinued by Sea to Summit. If you're looking for a similar waterproof daypack, check out their current lineup—the Ultra-Sil Dry Daypack and Big River Dry Bag series offer comparable performance.
Sea To Summit Waterproof Backpacks
Check Latest PriceFrequently Asked Questions
What's the difference between waterproof and water-resistant?
If you've shopped for outdoor watches or gear, you've probably seen both terms thrown around. They sound similar, but there's a big difference. Water-resistant handles light splashes and drizzle—that's it. Waterproof means you can fully submerge the bag and your stuff stays dry. The Sprint is truly waterproof—I've dunked it in creek water and everything inside came out bone dry.
Is the Sea To Summit Sprint fully waterproof?
Yes—I tested it under direct creek flow, and the interior stayed completely dry. The roll-top closure combined with tape-sealed seams provides reliable protection in real conditions.
What's the capacity and is it enough for travel?
20L official capacity. If you roll fewer times, you get a bit more space. It's enough for day trips and light travel—not meant for week-long expeditions.
How durable is the fabric?
210D nylon body with 420D reinforced bottom. During my water testing, the bottom scraped against rocks repeatedly with no visible wear.
Is it comfortable for all-day carry?
The S-curved straps and mesh back panel with a center channel make it comfortable even on longer days. The padding wicks moisture well, so it doesn't get soggy after sweating.
Can I use it for travel, not just outdoor activities?
Absolutely. I use it for rainy commutes, airport transfers, and city travel just as much as outdoor trips. It's not just an outdoor pack—it's a genuinely versatile waterproof bag.
The Bottom Line
If you're looking for a waterproof travel backpack that can handle real conditions—not just marketing-speak "water-resistant"—the Sea To Summit Sprint 20L is the one I'd recommend. It's been through creek crossings, monsoon commutes, and everything in between. Still going strong.
The waterproofing is legit, the carry is comfortable, and it's light enough that you don't notice it until you need it.
Looking for more waterproof travel gear? Check out our guide on best waterproof travel backpacks for more options.