Merrell Agility Peak 4 GTX Review: A Protective Trail Shoe for Wet, Muddy Miles

Introduction

The Merrell Agility Peak 4 GTX is the waterproof update to the Agility Peak 4 that launched in 2021. The core shoe stays the same: a protective trail shoe with a cushioned midsole, a rock plate, a protective toe cap and a Vibram outsole with 5mm lugs. The headline addition is the waterproof membrane, and it pushes the price to £155, up from £125 for the standard version.

The shoe weighs 328g (11.6 oz) for men in a size 8, with a 6mm drop. It is built for rugged, wet trails rather than speed, and after taking it out for a 10-mile run across the South Downs in heavy rain and deep mud, the picture is fairly clear about who it suits and who it does not.

Who This Shoe Is For

This is a shoe for comfortable miles on rough, wet terrain, not for racing. The cushioning is generous but firm, and the 328g weight is noticeable. It handles the transition from road to trail fine for a kilometre or two, but the soft lugs are not built for extended road running and can feel uncomfortable after that.

If your typical run involves mud, grass, rocks and unpredictable footing at a steady pace, this shoe fits that brief well. If you want something fast, look elsewhere.

Fit and Comfort

The fit runs true to size, with a comfortable amount of space in the forefoot. The jacketed upper is a good balance of flexibility and durability, and the flex connect grooves across the forefoot let the shoe bend naturally for better control. The semi-gusseted, curved tongue straps down nicely and there is a solid heel lock, so the lockdown fit is secure without any pressure points. It is a genuinely comfortable shoe for long, slow trail outings.

Grip and Midsole Feel

The moderately aggressive Vibram outsole was excellent in wet, slippery mud. On a day when a less aggressive outsole would have meant slipping on every incline, the 5mm lugs clawed through with no issues at all. Vibram rubber has a strong track record here, and the grip inspired confidence on hard, wet trails as well as soft ground.

The cushioning deserves a mention too. It is firm rather than plush, with plenty of foam to soften impact without deadening the ground feel. That balance suits varied terrain, where you want protection but not a mushy ride.

How the Waterproof Membrane Performs

The GTX membrane does its job in the right conditions. Running through puddles at the start of the outing, no water came through at all, and feet stayed dry for a good 20 minutes of steady running.

The catch is the classic one with waterproof running shoes: once it starts raining properly and you are wearing shorts, water drips in over the top of the collar and your feet get wet regardless. For running, that makes the membrane of limited value. For hiking, where you are more likely to wear waterproof trousers that channel water away, it works much better.

Things to Consider Before Buying

There are two main trade-offs. First, this is a heavy shoe at 328g, heavier than the non-GTX Agility Peak 4, and it is not a shoe for speed or racing. Second, the £155 price is a steep premium over the £125 standard version for a feature that many trail runners will not fully benefit from, since wet feet are often unavoidable in rain anyway.

If you do not need the waterproof membrane, alternatives worth considering include the Saucony Peregrine 12, which is lighter and more versatile, the Hoka Speedgoat 5, similarly versatile but not waterproof, or the Salomon Speedcross 6 if you want something more aggressive that also comes with a waterproof option.

Buying Advice

For hikers who wear waterproof trousers and want dry feet from below as well as above, the GTX version makes sense as an investment. For trail runners who mostly run in rain, the standard Agility Peak 4 at £125 is the smarter buy, because you lose little that matters and save £30.

Conclusion

The Merrell Agility Peak 4 GTX is a solid, reliable trail shoe with excellent grip, a comfortable secure fit and good protection for rugged, muddy terrain. It does the job well without doing anything spectacular, and whether the waterproof membrane is worth the upgrade depends entirely on how you use it: great for hikers, questionable value for most runners.