On Ultra Review: A Long-Distance Trail Shoe Built for All-Day Comfort

Introduction

On has been busy expanding its trail running lineup, and the new On Ultra sits at the top of it as the brand’s long-distance option. The idea is simple: a shoe built for long days on the trail with all-day comfort and solid underfoot protection. We took it out for a first run on a mix of road, sand, and hard-packed stone to see whether it lives up to that brief, and how it compares with On’s earlier trail releases.

At a £150 retail price in the UK, it sits alongside On’s Fell and Trail shoes at exactly the same price point, which makes it worth asking what actually separates the Ultra from its siblings.

Who This Product Is For

The Ultra is aimed at runners who want one shoe for long trail days: enough cushioning to stay comfortable over hours, enough protection to handle rocky ground, and a versatile outsole that can cope with mixed surfaces. It is not pitched as a race shoe or a fast, minimal option. If your running involves long, steady efforts over varied terrain, this is the audience On is designing for.

Shoe Stats and Construction

Our pair in a UK 9.5 came in at 319 g, with a 30 mm heel stack and 22 mm under the forefoot on a Vibram sole system. Flip the shoe over and you find a Vibram Megagrip Litebase rubber outsole with a mix of 4 mm lugs through the centre and deeper 6 mm lugs around the perimeter.

Construction is where the family resemblance to On’s other trail shoes shows up most clearly. The dual-layer engineered mesh upper looks and feels close to the On Trail shoe, and the same X lace system returns, with two cords crossing over the midfoot to deliver an even, secure lockdown. Protection up front comes from a substantial toe bumper, while a heel cradle adds structure at the back and a pull tab makes the shoe easier to get on and off.

One small but welcome detail: the stock insole is genuinely good, with real cushioning, shape, and support, and it stays put inside the shoe. It is a reminder of how much a quality insole adds to overall plushness, especially compared with the flimsy paper-like insoles some brands still ship.

Fit, Upper and Lacing

On sent the Ultra in its regular plus fit, the wider option compared with the standard regular fit. That extra width made a clear difference. The shoe runs true to size with good length in the toe box, and the roomier toe is noticeably more accommodating.

Our recommendation for most runners is to choose the regular plus fit unless you have a genuinely narrow foot. The regular fit reads more like a precision, very narrow cut, while regular plus is close to a standard fit from most other running brands. That said, the toe box still tapers quite early and is narrow at the very end; a squarer shape would improve it.

The X lace system gives a firm hold around the midfoot, but early in the run there was a little movement in the heel. The ankle collar gapes slightly, and re-tying the laces helped, though the back end of the shoe never felt fully locked in.

Cushioning and Midsole Performance

On pitches the Ultra as a deeply cushioned trail shoe for all-day comfort, and the stack is slightly deeper than the Trail shoe, though only by 3 mm, which is a modest step up for a shoe carrying the Ultra name. Pushing into the foam, it does not feel especially soft. Compared with some of the modern foams in today’s trail shoes, the midsole reads as on the firmer side.

In practice, the extra stack still helped. It delivered a bit more comfort on road sections at the start of the run and a fair amount more underfoot protection on rocky and stony ground. But calling this a deeply cushioned shoe would be a stretch. There is more substance here than in On’s Trail shoe, just not the plush ride the marketing suggests.

Outsole Grip and Ground Feel

The Vibram Megagrip Litebase outsole is the standout carryover, and it was one of the strongest features on the earlier Trail shoe too. On dry sand, the mixed 4 to 6 mm lug pattern gave good traction and a decent amount of ground feel for a cushioned shoe, and the ride felt planted throughout.

Hard, compacted stony trails were handled well too. Our test run happened in hot, dry conditions with no wet rock or slippery mud, so we cannot claim firsthand wet-weather results, but Megagrip’s reputation on wet, rocky terrain is well established. With this outsole and lug design, the Ultra looks like a shoe that can cope with most underfoot conditions, which makes it genuinely versatile, particularly for UK trails. Breathability from the mesh upper also helped in the heat of a 29-degree test day.

Things to Consider Before Buying

The main hesitation is cushioning depth. For a shoe designed specifically for long distances and all-day comfort, we would have liked more of it underfoot. If you want a genuinely plush max-cushion trail shoe, this may not deliver the ride you are expecting.

Second, the Ultra shares a lot with the Fell and Trail shoes: the same price, the same sole system, the same lace setup, and a very similar upper. Without the wider regular plus fit, the differences would be hard to spot. It would be good to see On differentiate these three shoes more clearly in future, with different uppers or midsole compounds.

Finally, heel lockdown is only adequate. It can be managed with careful lacing, but runners who demand a locked-in heel may want to try before buying.

Buying Advice

Buy the On Ultra if you want a true-to-size, versatile trail shoe with excellent Vibram grip, good underfoot protection, and a fit that works for average-width feet in the regular plus version. It is best suited to long, steady trail runs over mixed, mostly dry terrain rather than short, fast efforts. If deep cushioning or a locked-down heel is your priority, consider testing it first or looking elsewhere.

Conclusion

The On Ultra is an easy shoe to like on grip, fit, and versatility, and we preferred it to the On Trail shoe thanks to its roomier regular plus fit and slightly deeper stack. But as a long-distance shoe, it stops short of the deep, all-day cushioning its name implies, and its similarity to On’s other trail models makes it harder to justify as a distinct purchase. A capable, versatile trail shoe with real strengths, held back by modest cushioning and a familiar design.