Soft Flasks vs Hydration Bladders: Which Trail Vest System Fits Your Run
Once you've settled on a vest capacity, the next decision is how you actually want to carry your water. Trail vests generally support two systems — soft flasks in front pockets, or a bladder in the main compartment — and the right choice comes down to how you like to drink and what else you're carrying.
Soft flasks: fast, front-mounted access
Soft flasks sit in dedicated pockets on the front of the harness, usually holding around 500ml each. Because they're right in front of you, you can grab, sip and stow one without breaking stride — no reaching over a shoulder or fumbling for a bite valve. They're also easy to refill individually at an aid station, and an empty flask collapses down instead of sloshing around.
This is the system built into the LECAMO ROOT5 and LECAMO ROOT8, both of which use twin 500ml front hydration pockets, and it's also how the LECAMO ROOT18 handles quick-access hydration up front, alongside its larger rear storage for everything else.
Hydration bladders: more volume, hands-free
A bladder sits in the main compartment with a drinking tube routed over the shoulder, typically holding 1.5–2L in one reservoir. The appeal is volume and convenience — you can sip constantly without reaching for anything — which matters most on long, remote, or poorly-supported routes where refill points are far apart.
The tradeoff is weight distribution: a full bladder sits centrally on your back rather than balanced across the front, and topping it up mid-run is slower than swapping a flask.
So which should you choose?
- Training runs, races with aid stations, or anything under a few hours — front-mounted soft flasks are usually the better fit. Quick access, easy refills, no sloshing.
- Long, remote, or unsupported efforts — a bladder's extra single-reservoir volume can be worth the added centre-of-back weight.
- Not sure? — start with front-mounted flasks. They cover the vast majority of training and racing scenarios, and it's the system across the whole LECAMO ROOT range.
For help matching capacity to your typical run length first, see the Trail Running Vest Capacity Guide and How Much Water Do You Need for a Trail Run.