Merrell MTL Long Sky 2 review: A roomy shoe great for training on the trails

The Merrell MTL Long Sky 2 is a comfortable light fit thanks to effective updates

Merrell MTL Long Sky 2 shoes being tested by Fit&Well
(Image credit: Lily Canter)
Fit&Well Verdict

A solid all rounder that handles well in different conditions. The shoes offer a spacious fit, particularly around the toe box, but be aware that debris can easily slip in. Perfect for easy training runs but may lack midsole comfort over longer distances.

Reasons to buy
  • +

    Environmentally friendly

  • +

    Spacious fit

  • +

    Breathable and lightweight

Reasons to avoid
  • -

    Too wide for narrow fit

  • -

    'Gaiter' product required to keep out debris

  • -

    Thin midsole and lack of cushioning

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Better known for their hiking shoes Merrell is now making headway in the trail running world with the newly released MTL Long Sky 2 promising to be 'ready for anything'. 

It is a bold claim but one which the shoe largely lives up to, making it one of the best trail running shoes currently on the market.

What makes it stand apart from other brands is the spacious fit which easily accommodates the natural swell of feet on longer trail runs. This is supported by the lightweight and breathable material which is made up of some vegan and recycled materials.

The 5mm lugs handle most terrain with confidence and the relatively thin midsole and 4mm drop make for a responsive, stable run.

The shoe may look a little clunky and be less sexy than competitors but the fit is actually extremely comfortable, and is akin to wearing running slippers.

Here's what we made of it, after testing it out on several lengthy trail runs.

Price and features

Not the cheapest pair of trail shoes the Merrell MTL Long Sky 2 retail at $140/£115. This is a pretty standard price for a robust pair of off road shoes these days and is marginally cheaper than top brand models like Saucony Peregrine and Hoka Speedgoat. 

Design and technology

Admittedly this is not the best looking shoe on the market and is not going to win any aesthetic design awards. Because it is a spacious shoe it looks rather cumbersome rather than sleek and speedy.

Color wise there is only one option but it is unisex which is refreshing to see. The Long Sky 2 teal and burnt orange design is not particularly striking but is inoffensive enough to suit most tastes.

Merrell MTL Long Sky 2 resting on cardboard box

(Image credit: Lily Canter)

The FloatPro Foam is designed to dry quickly so it is suitable for changing and unpredictable weather conditions. The upper has an extremely breathable mesh and the supporting TPU material offers greater durability than traditional EVA. Merrell is also making great strides in sustainability with 100% recycled TPU, mesh footbed cover, tongue webbing and laces.

The MTL Long Sky 2 sticks with the Vibram MegaGrip rubber outsole which continues to provide effective traction on wet and dry surfaces.

Merrell MTL Long Sky 2 underside

(Image credit: Merrell)

Interestingly the Long Sky 2 has moved away from the EVA midsole of its predecessor which was promoted as a light pronation control shoe thanks to its medial post (a strategically placed ‘firm spot’ in the shoe). While the MTL Long Sky had an 8mm drop, the Long Sky 2 has been altered to a more responsive 4mm drop fitted with a FloatPro Foam midsole.

For a runner like me who likes to move with the terrain rather than be supported by a more rigid structure and deeper drop, this is a welcome change. This model has also been upgraded with lighter, more sustainable material.

The shoe now comes with a gaiter d-ring, a feature which did not appear on the earlier model. This makes it easier to fit a gaiter (a garment you wear over the end of your trousers and top of your shoe) to prevent small stones and debris falling inside.

Fit, feel and comfort

Slipping on these shoes does feel like pulling on a pair of cosy slippers. That seems to be down to two things. Firstly the wide, airy toe box gives your toes plenty of room to wiggle. This is reinforced though, so unlike slippers you don't have to worry about stubbing your big toe. And secondly the internal bootie locks your feet in making them feel snug.

While I appreciated the wider fit, even though I have standard size feet, it did mean that lots of debris slipped in. The bootie may be snug around the mid foot but there is still a gaping hole around the ankles. The idea is that you fit a gaiter to the shoe but I would have preferred a narrower fit around the ankle or an integrated collar and tongue like the one found on the Scarpa Golden Gate ATR and Ribelle Run.

Merrell MTL Long Sky 2 being tested by Lily Canter

(Image credit: Lily Canter)

Despite the spacious feel the shoes fit well (I always go half a size up) and I had no issues with rubbing. For everyday training up to half marathon distance or gentle recovery runs these felt like a comfy reliable pair of shoes. But I was not confident enough to wear them during a trail marathon because the soles of my feet became a little sore around the 20k mark. They lack the cushioning I prefer for long distance runs but are a great all rounder for easy running and dry quickly when splashing through puddles, bogs or streams which is a real bonus.


These are actually not a bad pair of road to trail shoes and felt pretty comfortable on both terrains. But they came into their own when traversing lumpy fields because they can handle soft variable surfaces with ease. However there was a bit of slippage on wetter and rockier terrain and I didn't feel the 5mm lug was as grippy as my all time favourite Saucony Peregrine 12s. 

User reviews

Runners appear to have nothing but praise for these shoes and unlike myself found them extremely effective on all terrain. 

"My go-to trail runners here in Colarado for technical trails. I wore these shoes while I summited five peaks in two days, during a 28-mile trail run on the Maroon Bells Four Pass Loop. Now that I’ve put close to 200 miles on these shoes, I’m stoked to have found one of the most versatile trail runners I’ve ever worn," exclaimed one ultrarunner.

But another runner agreed that these may not be the best shoe for super long distance due to "a lack of cushioning for those truly long events that span more than half a workday."


The Merrell Long Sky 2 shoes are definitely reliable; they feel light and breathable on the foot while providing plenty of protection against rugged trails. 

After testing them out, we think they’re best suited to runners looking for a wider fit who run on local trails. While they aren’t the most technical shoe available – and their aesthetic won’t be to everyone’s taste – they are a great all-rounder.

Also try

Saucony Kinvara 12

(Image credit: Saucony)

Saucony Kinvara 12

We’d be remiss not to mention one of our top-rated trail running shoes that doubles as a road shoe: the Saucony Kinvara 12. Slim, light-weight and surprisingly durable, it’s technically just a straightforward running shoe. This means you can take it on roads and marathons, if you’re so inclined – but it works well as a responsive trail runner, too.  

Scarpa Spin Infinity

Scarpa Spin Infinity

(Image credit: Scarpa)

The Scarpa Spin Infinity, similarly priced to the Long Sky 2, are an extremely comfortable and cushioned pair of trail shoes which will keep your feet feeling fresh for marathon distance and beyond. 

Lily Canter

Lily Canter is a freelance money, health and lifestyle journalist with more than 20 years' experience. She writes about fitness for Runner's World and Trail Running magazines and focuses on personal finance for Yahoo! Finance UK, Metro, The Guardian, and the Mail on Sunday. In her spare time she is an ultra-runner, canicrosser and running coach. She also co-hosts the award-winning podcast Freelancing for Journalists.