Mammut Sertig III Low GTX Review: The Comfort-Value Hiking Shoe

The Mammut Sertig III Low GTX is the comfort-value shoe in Mammut's hiking line: a GORE-TEX lined day-hiker that puts cushioning and dry feet ahead of technical mountain ambitions. It costs £135, weighs around 384g per shoe in UK8, and runs an 8mm heel-to-toe drop over a high-rebound EVA midsole. That is a soft, forgiving platform for exactly the kind of walking most of us do most weekends.

I rate it 4.5/5. It sits alongside the value picks in my best waterproof trainers roundup, and if you want dry, cushioned feet on mixed British trails without paying up for a full mountain shoe, it earns its place.

Who the Sertig III is for

This is a day-hiking shoe for people who prioritise comfort. The high-rebound EVA midsole and Ortholite insole give it a plush, trainer-like feel that works well on long, flat-to-rolling routes: chalk downland, the Jurassic Coast path, New Forest gravel and estate tracks. If you spend your walking miles on the softer half of the terrain scale and want your feet to feel fresh at the end, the Sertig III is built for you.

It is also a strong pick if you split your week between trail and everyday wear. The low-cut cut, muted colourways and clean mesh upper look at home off the hill, and the £135 price makes it easier to justify than a dedicated mountain shoe you only wear on weekends.

Who should look elsewhere: if you routinely carry a heavy pack over rock, scree or steep, technical fell ground, you will want more underfoot support and a burlier outsole. For that, my Mammut Aenergy Trail All-Mountain Low GTX review points at a shoe with more mountain intent. The Sertig III is the comfort-value option, not the all-mountain one.

Waterproofing: the GORE-TEX lining

The Sertig III uses a GORE-TEX Footwear lining, which is the reliable waterproof-breathable membrane you want for the wet British half of the year. In practice that means wet grass, puddles, bog splash and light rain stay on the outside, while foot sweat vapour escapes rather than soaking your sock from within. On dewy downland mornings and after coast-path drizzle, my feet stayed dry.

The limit is the low cut, and it is worth being honest about it. A low shoe is only ever waterproof up to the ankle collar. Step into water deeper than the collar, or spend an hour ploughing through shin-deep saturated bog, and water comes in over the top regardless of how good the membrane is. That is a physics limit of every low-cut GORE-TEX shoe, not a Sertig III fault. For deep, sustained bog and stream crossings you want a mid boot or gaiters. For everything short of that, the lining does its job.

Grip and outsole

The Sertig III runs Mammut's own Swiss Design outsole, tuned to keep grip in low temperatures rather than going stiff and skiddy in the cold. The lug pattern is moderate: enough bite for wet grass, packed earth, gravel and forest trail, and confident on chalk when it is dry. It is a mixed-terrain grip profile, not an aggressive mud-shedding fell sole.

On slick wet chalk and greasy clay, which is about the most treacherous surface the South of England throws at you, treat it with the same respect you would any moderate-lug shoe. It holds well for the category, but deep claggy mud is not its strength. For the trails this shoe is designed around, the grip is well judged.

Cushioning and fit

Cushioning is the Sertig III's headline. The high-rebound EVA midsole is soft and springy underfoot, and the Ortholite insole adds step-in comfort that lasts. The 8mm drop is a gentle, middle-of-the-road figure that suits a natural hiking gait without forcing your calves to work like a low-drop trail runner would. Over a long day this is a shoe that stays kind to your feet.

The double engineered mesh upper wraps the foot comfortably and needs little breaking in. Fit runs true to size for me, with a medium-width last and a reasonably roomy toe box. If you have wide feet, it is accommodating; if you have narrow feet, size normally and lace it snug. As with any low-cut shoe, take your usual walking-shoe size rather than sizing up.

Colours

The Sertig III comes in four colourways, and Gabbro is the pick: a muted, stony grey-brown that hides trail dirt, works on and off the hill, and is the one I would buy. It is the hero shot at the top of this review.

The other three are worth a look if you want something different:

The stealth pick: all-black, most at home in town.

Deep blue, a touch more colour without shouting.

The warmest tone of the four, good if you want the boldest option.

Specs at a glance

Pros and cons

• Soft, high-rebound EVA cushioning that stays comfortable over long days
• Reliable GORE-TEX Footwear waterproofing for wet British walking
• Clean, muted looks that work on trail and in town
• £135 for a GORE-TEX cushioned hiker is strong value
• True-to-size fit with a roomy toe box and little break-in

• Low cut lets water in over the collar in deep bog or stream crossings
• Moderate lugs, so not a mud-shedding or technical-terrain sole
• Comfort-first platform lacks the support for heavy loads on steep, rocky ground

Verdict

The Mammut Sertig III Low GTX earns 4.5/5 as a comfort-value day-hiking shoe. You get GORE-TEX waterproofing, a genuinely cushioned high-rebound EVA ride, an 8mm drop and Mammut's own Swiss Design grip for £135, in a shoe that looks as good in town as it does on the coast path. For dry, cushioned feet on chalk downland, forest tracks and rolling trail, it is an easy shoe to recommend.

Buy it if you want comfort and dry feet on mixed British trails and are not routinely hauling a heavy pack over technical mountain ground. If that is you, look at the Mammut Aenergy Trail or the rest of the waterproof trainers hub instead. Gabbro is the colour I would choose.

FAQ

Compare it against the other value picks in the best waterproof trainers roundup, including the Merrell Accentor Sport 3 GORE-TEX and Merrell Moab 3 GORE-TEX.