On Running Ultra Vest: A Stylish and Functional Companion for Your Runs

The quest for the perfect hydration solution in running is something I’m always trying to find. I have tested – with really positive outcomes – countless handhelds and waist packs, and at least a half dozen vests. Each has its benefits as well as its drawbacks, and it all really comes down to personal preference and what you can live with while you’re out there running, whether it’s for an hour or 16 hours. My newest test comes from On – in the form of their brand new Ultra Vest.

Renowned for their cutting-edge running shoes that have garnered a loyal following among athletes, On’s foray into the world of hydration packs is nothing short of exciting. Leveraging their expertise in crafting top-tier footwear, they’ve seamlessly transitioned their innovative approach to design and performance to the realm of hydration solutions. This venture marks an exciting expansion of their product lineup, reflecting their dedication to enhancing every aspect of a runner’s journey.

See all our posts about On Running.

A reliable running vest can make all the difference in your outdoor adventures – if it can provide convenience and functionality. As an avid runner, you understand the importance of a well-designed vest that not only looks great but also enhances your overall running experience.


On is known for amazing visuals on their running shoes, and thus its no surprise that their Ultra Vest catches the eye as well. Its undyed white color with subtle detailing exudes a sense of simplicity and elegance. The vest’s streamlined profile and thoughtful aesthetics make it an attractive accessory that complements any running attire.

The simplistic and basic color set is really solid (and being undyed – better for the environment), but some runners may find the limited color options less appealing due to concerns about visible stains and wear over time. As someone with a very bright and eclectic running wardrobe overall, I actually really like the simple white vest over a bolder color anyways in this case.


Crafted with precision, the On Running Ultra Vest showcases impeccable construction. The high-quality materials used (Main Body – 85% recycled polyamide, 15% elastane; Pockets – 41% polyamide, 41% recycled polyamide, 18% elastane) ensure durability and longevity, even through the toughest of workouts.

The attention to detail is evident in the stitching, which not only contributes to the vest’s visual appeal but also reinforces its structural integrity. With thoughtful design elements, this vest stands up to the rigors of your active lifestyle.

The material is super stretchy and forgiving. It is ultralight yet tough, and has provided the ability to achieve a stable fit that isn’t all tied up in buckles and straps. The patented-pending closure system is super unique and really allows you to adjust the vest’s placement to best suit your body. While the body of the vest is stretchy and forgiving, the bottle pockets are made with non-stretch materials to minimize the dreaded bottle bounce.

It is also one of the most packable hydration vests I have ever worn. Packability isn’t generally something considered in running vests, but after seeing it packed down into a hand-sized package INCLUDING the water bottles.


The Ultra Vest’s fit is really great and SUPER light. It weighs in at a miniscule 4.4 ounces (without water) so it’s almost as if you aren’t running at all. This could be used for longer lengths, I think the sweet spot is in the medium distance runs. There is a good amount of storage options, but this vest almost seems more destined to run fast in with its lightweight fit.

I wear a Large in clothing but elected to try an XL as I have found there’s nothing worse than a too-tight vest. The XL provided plenty of room and I was able to find the right secure fit. Its ergonomic design contours to my body well and provided a snug yet comfortable fit that stayed put during my runs.

Instead of buckles, as many vests utilize, the Ultra Vest is secured using an elastic patented-pending closure system. It makes tightening and loosening on the fly super simple – and customizing the optimal fit a breeze.


The vest comes with two integrated Hydrapak soft flasks, which are kept in place by bungee loops to keep them from bouncing around. There is also internal padding inside the pockets to provide just a little more cushion between water and body. There are both 5L and 10L options. The 10L version comes with a dedicated hydration pocket and 5L bladder (which are not in the 5L version) to allow for additional hydration storage.


It includes thoughtful storage solutions such as two elastic pockets beneath the water bottle compartments and additional side pockets for your convenience. On the left shoulder, a dedicated zipped pocket secures essential items like keys and money, while the back boasts an elastic pocket suitable for storing larger items like a jacket. Moreover, the vest prioritizes sustainability and cleanliness, featuring a specialized pocket for packing out garbage like food wrappers and hydration gel packets, complete with an easy-to-clean lining.

For longer excursions, the embedded daisy chains allow you to carry poles effortlessly.


Outside of storage, the Ultra Vest includes reflective additions to enhance safety during low-light runs, ensuring you’re visible to others. As an additional bonus, an emergency whistle is included, underscoring the vest’s commitment to your safety and overall outdoor experience. Altogether, this light little vest stands out as a reliable companion for most running adventures.

For Consideration:

We reviewed the 5L version – which is perfect for a runner like me who maxes out most runs at 8-10 miles on most runs (with an occasional 20 miler a few times per year). I don’t need to prepare for huge excursions, so having ample hydration, thoughtful storage, and a solid fit is all I really need. My guess is many of you out there would feel the same way.

If you are like our blogger Drew Roberts, who is constantly running double digits as merely training runs for 50k+ events, the 10L version of the Ultra Vest is likely the better option. It has the same features and has added bonuses of additional hydration and enhanced storage options.


Honestly, we have been pretty pumped about our initial testing of the inaugural voyage of On into the running vest sphere. The Ultra Vest is classically stylish, super comfortable, and we really found the groove with it on our recent trip to the Hawaiian Islands.

If you’re in search of a new running vest option, definitely consider taking the Ultra Vest for a test spin.

On Ultra Vest 5L $150


  • Capacity: 5L
  • Color: Undyed white with subtle detailing
  • Material: High-quality, durable materials
  • Adjustable straps for a customizable fit
  • Multiple pockets for storage, including energy gels and hydration flasks
  • Streamlined and lightweight design for optimal comfort



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Thank you to On for providing us with a test vest. Please read our transparency page for info on how we do our reviews.

About Author

Matt Rasmussen lives in Keizer, Ore. with his wife and three daughters. He enjoys watching hockey, going to as many breweries (618) and wineries (152) as he can, and all things Canada (he was born there). Matt was raised as a baseball player and officially transitioned over to running in 2010.

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