How to Choose Ski Mountaineering Boots

Here we explain from start to finish everything you need to know about boots for ski touring or ski mountaineering.

Boots for ski touring: ascent-descent. Photo: barrabes

A ski mountaineering or ski touring boot has to meet several requirements:

  • Due to its use on ascents, it should be as lightweight as possible.
  • It should be the most similar in performance to alpine boots on descents
  • It must have a cuff that can be unlocked for ascent movement
  • And also, it should work like a mountaineering boot for those occasions when you have to take off your skis and take on ridges, corridors, slopes, etc

Difficult? Of course. Impossible? As we are going to see, less and less.

Alpine areas without skis in ski touring , boots with crampons: Photo: Scarpa

What is a ski mountaineering (skimo) boot?

A ski mountaineering boot is, basically, an alpine ski boot that offers the possibility of unlocking the upper cuff to facilitate the action of walking with skis on.

The two main differences with an alpine boot are:

  • Includes rubber sole with heel to be used as a mountaineering boot
  • Curvature (rocker) to facilitate movement
  • The standard that regulates its fittings is ISO 9523

In our article about wow to choose alpine ski boots we explain some general concepts about how to get the size right, what flex is, the Mondo Point size, ISO 9523, ISO 5355, which are mostly valid for this article. If you are not clear about any of these concepts, we recommend that you read it.

As we say, they are valid concepts for ski touring boots...except for some very important nuances. In addition to explaining all the types of boots that we can find, we will clarify these nuances in this article.

Hiking with ski boots. This and other much more technical situations face ski mountaineers

Compatibility Between Ski Touring Boots and Bindings

Before starting, it must be clarified that incompatibilities between ski touring boots and bindings are increasing due to:

  • The different existing binding systems
  • The modern freeride boots, or ultralight competition boots, with special needs
  • The differences in length between one model of mountain ski boot and another, even between the same size and system
  • The little or no adjustment range of the heel pieces of some bindings

And the standard that regulates bindings, ISO 9523, is obsolete: it only refers to track-mounted / frame bindings, and not to tech bindings. That is to say: a boot with inserts can comply with the standard because it is also compatible with these bindings, but if we use it with an tech binding (the usual thing), at that moment we do not use it according to the standard.

There''s more: ISO 9523 refers exactly to heel and toe measurements. In a system where the foot moves, there are incompatibilities even between ISO compliant boots. For example, because the design of the shell in the toe (which is not marked by the standard) causes it to collide with the binding when walking, potentially breaking, and it only works with the appropriate binding for it. There are also boots that only accept inserts and are not the norm.

As in addition to this mess, there are different types of binding systems on the market. Be sure your boots are compatible with your bindings.

Because brands are reluctant to recognize certain incompatibilities, it is advisable to always test the boot and binding before purchasing, or inquire about it.

It is also advisable to check the compatibility of your new boots with the crampons you usually use.

Fundamental factors in choosing a ski mountaineering boot

1. Weight

Unlike alpine ski boot models, weight - that of the boot, not that of the skier - is one of the most important factors when choosing a ski mountaineering boot. In fact, it is the first piece of information that almost everyone looks for.

Logical, if we take into account that in addition to descending, we have to ascend with them.

Our advice? Once we know the appropriate use for us (more ski-mountaineering, more freeride, etc.), we will look for the boot to be as light as possible, without going to the extreme of the minimalist competition boot. But always within the appropriate use for our type of ski. It will not be a good idea to choose the most extreme minimalism for freeride to save grams, for example.

Descending the Salterillo tubes, Benasque. Photo: Daniel Vega

2. Range of Motion

The range of motion of a boot is usually known as the combination of two parameters:

  • The width of the arc that the cuff describes forward and backward when unlocked.
  • The amount of effort required to move it.

What advantages and differences do different ranges of motion have?

The biggest advantage of a wide range of motion is that it does not limit us. When climbing, on slight slopes we will take longer steps, and on steeper slopes, shorter steps, according to our need. We decide the length of our stride, not the boot.

So why don''t all boots have a wide range of motion?

A longer range of motion is achieved by "eliminating" elements of the boot when manufacturing it, especially in the tongue area. Freeride boots would lose some support, protection and performance, because they are more oriented towards descent, so their range of motion is narrower.

That''s why it is said that lightweight boots penalize performance on descents, and boots closer to freeride have something of a penalty on ascents.

Another thing happens: in almost all cases, the cuffs with the greatest range of motion are the ones that present the least opposition, due to their own configuration with less material. Step by step, the boot requires less effort, which is noticeable at the end of the day.

3. Size and Last

The most honest advice we can give you is to put yourself in the hands of a specialist. The ski mountaineering boot must not only fit you well when going downhill, but you must also walk with it, and depending on your foot, this combination can be complicated.

But in general, we must always keep in mind that with our boots we are going to walk much longer than we are going to ski, so a boot that causes friction when ascending is not going to be a good companion, no matter how well they perform on the descent.

Take your time choosing your size and choose the last that best suits your foot type.

In our article about alpine ski boots we explained how to find out your MP size (MondoPoint) and other interesting aspects. But regarding half sizes, we would like to point out:

  • Normally alpine ski boots share a shell between two sizes. A 27 and a 27.5 have a different plastic insert under the liner, a different insole or a different liner but the shell is the same.
  • That is why the half-number difference between a 27.5 and a 28 is more noticeable than the difference between a 27.5 and a 27. If we are wrong by half a point, it is easy to correct by customizing them if we are talking about the same shell. If there is a jump to a larger shell, then it becomes more complicated.
  • Well: some brands and models of mountain ski boots share the shell in reverse: The 27.5 shares it with the 28 instead of the 27.

Find out about this when deciding your size. Be careful with rounding up or down when it involves changing the shell.

A factor to take into account that can complicate the matter a little is the little information on last widths that ski touring boot manufacturers usually offer. Unlike alpine boots, many skimo boot manufacturers do not specify the shape of their boots. Curiously, the majority of “unspecified” lasts are some of the, at first glance, most suspiciously narrow.

If you have had problems with boots that are too narrow before, don''t hesitate, get advice. Not only do some boots not specify the last, but many also do not specify the flex rate.


As with touring skis and bindings, we find three categories:

  • Lightweight/competition
  • All-round
  • Freeride

As it could not be otherwise, the lines between categories are blurred: modern construction methods, minimalist designs, and materials such as carbon fiber have jumped from competition to the all-round category and even freeride.

More and more skiers are choosing boots under 1.3 kg per foot for all-round use because, in recent times, materials such as pebax, grilamid and composites have managed to greatly reduce the weight. managing durability and resistance very well.

Scarpa F1 LT, versatile and ultralight touring boot

Which skimo boots should you choose?

Two basic tips:

  • Once we know the appropriate use for us (more ski-mountaineering, more freeride, etc.), we will look for the boot to be as light as possible. We will not choose a boot that does not adapt to our needs to save weight.
  • If you don''t know exactly what boots you need, the versatile mid-range models are almost certainly for you; neither the ultralight ones, nor the cheapest ones.

And the fact is that the majority of current multipurpose boots are light: weight reduction thanks to new designs and materials, which has also not been associated with a reduction in lowering performance for a long time. So, more and more skiers and “ski mountaineers” are opting for this type of boots, with much more mobility as they are unlocked and much lighter.

Dynafit Hoji PX, versatile all-terrain medium

Of course: be careful with extreme minimalism, because those grams come out from somewhere. Durability, and certain aspects related to comfort (such as the conformable parts of the boots), thermal insulation and impermeability are usually the victims that the scales sacrifice first.

They are boots that climb very well, but with intense use the soles, clasps, liners and shells will suffer more than necessary, being more prone to breakage. Those looking for performance above all, go ahead, those looking for durability and reliability may prefer a less extreme model.

Atomic Backland Pro W heat molded, women''s version. Multipurpose lightweight boots

What kind of skier will choose what type of boot?

Competition skiers will obviously be looking for high-performance competition boots. They are imitated by the fastest amateur skiers who are looking for performance and shaving off grams.

Atomic Hawx Ultra, free ride boots

And in the realm of total downhill predilection, certain freeride models up to 130 flex are actually lightweight, unlockable, rubber-soled versions of a high-end alpine ski boot.

Perfect allies for the most aggressive freeriders in search of lines at high speed and with “lots of air”, or for those piste skiers who occasionally go off piste.

Freeride boots. Atomi Hawx Ultra
All Ski Gear at Barrabes

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