What to Wear Under Ski Pants?

When gearing up for a fun day out on the slopes, layering is incredibly important. You might think that you only need to go out in your pants, gloves, and jacket, but doing so can cause you to become quite cold. That’s especially true on freezing days or windy peaks. To prevent that, you need a good base layer.

If you want to stay warm while skiing in frosty conditions, you need to wear something under your pants. That extra reinforcement may not seem important at first, but it’s vital when it comes to fighting the cold.

This article will break down what exactly you should wear under your ski pants, how to choose the right clothing items, and explain why certain people pick specific options over others.

The Purpose of a Base Layer

Before getting into specifics, I must first cover why it’s important to wear a base layer in the first place. No matter how strong or durable your pants are, they will never hold up to frigid temperatures.

They might get the job done on a light or sunny day, but few models have what it takes to stand up to the elements on their own.

To get that vital protection, you need a base layer. That will provide you with extra insulation and keep your skin warm regardless of how long you are on your skis.

Many popular pants are either shell models or use a basic fleece lining. Both measures, while fine, don’t do enough for truly frigid conditions. In addition, pants can also chafe or cause discomfort.

Having a soft layer underneath them cut down on both issues.

Thermals and Long Johns

When picking out your pant base layer, you need long underwear; commonly referred to as thermal underwear or long johns. You slip the clothing item on over your normal underwear as you would pants.

However, rather than being bulky like jeans or sweats, long underwear is quite thin. Even so, they still add warmth to your body by sitting snugly against your skin.

That light construction is vital because it offers insulation that won’t hold you back or weigh you down as you ski. You can wear a single pair for warmer days, or you can put on multiple if it’s going to be extremely cold on the mountain.

There are many types of long johns on the market, and they all come with their own benefits and drawbacks.

However, regardless of their differences, they give you an extra layer of cold protection you don’t get with normal pants. At the end of the day, that’s what you want.

Fabric Matters

Long johns are the best clothing to wear under your ski pants because they combine warmth and flexibility in a way that similar layers simply cannot match. However, picking out which material you want is not a simple process.

Classic long underwear tends to be made of cotton. While flexible, that’s not the most breathable material on the market. To get around that, many brands turn to more modern synthetic materials.

Synthetic options are much more affordable, flexible, and breathable than traditional cotton, but wool works as well.

Not only does the material wick away moisture to keep you sweat-free, it is also soft and incredibly comfortable. It’s quite warm too. So much so that many natural fiber layers use merino wool somewhere in their construction.

The material you use in your base layer largely depends on what you need from your long underwear. Synthetic is best for ventilation purposes, but wool is extremely soft and comfortable.

Weight and Length

The two other important aspects to consider when picking out long underwear for your ski pants are weight and length. As mentioned above, your base layer should be light and flexible, but there are heavier options if you need them.

Lightweight long johns are typically the best way to go because they give you a wide range of motion and serve as more of a “second skin” than anything else. In fact, most of the time you’ll barely know they’re on.

However, if you need something a bit sturdier, there are both mid and heavyweight options on the market. Heavyweight options are typically known as thermal weight or expedition underwear, and they can be worn just with pants or with pants and light long underwear. Midweight options can also be worn with a light base or on their own, they are simply less heavy.

Looking beyond weight, thermal underwear comes in two lengths: full and 3/4. Full options go all the way down to your ankles, while 3/4 models stop right above your ski boots so you don’t have to stuff more into your shoe. Both lengths work well, just pick the one you find more comfortable.

What Not to Wear

Thermal underwear is the only ski pant base layer you should use. Some people may try other options, but they simply do not work in the same way.

While it may seem like a good idea to throw on a regular pair of pants, like your everyday sweats or jeans, under your skiing ones, that’s a bad idea.

Skiing takes a lot of hard work, and it’s easy to build up a sweat. Regular pants, not made with special breathable materials, will soak through in no time.

Compression pants, or other similar clothing items, might seem like they could fill in for thermals. However, they are simply not as comfortable and not as equipped to handle frigid temperatures. Avoid those when possible.

Nothing At All

Of course, base layers are only needed for extremely cold or frigid days. If you’re hitting the slopes under a sunny sky or if you prefer to ski in warmer temperatures, you don’t have to wear anything except your normal underwear.

Not every condition calls for a base layer, and it’s fine to skip one if it gets too hot out. Just know that when you need extra insulation, it should only come from long johns.


Good layering practices are extremely important when it comes to staying warm on the slopes. No matter how strong or durable your pants are, there’s nothing wrong with getting a bit of extra protection for harsh environments or blustery days.

While you might think there are many items you can put under your ski pants, nothing compares to thermal underwear.

Do you wear thermal underwear? What is your favorite base layer for tough conditions? Let me know below!

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  • Jo

    Thanks. I am going on my first ski trip to Snowshoe WV in early Feb. I am from Florida so the cold concerns me. Your advice is great.

    • Christine

      Thanks for reading, and glad the article helped guide you in the right direction. Hope you’re trip goes well and you enjoy the snow!

  • Mike

    Very helpful, I am just getting back into skiing after several years and have spent lots of money on a beautiful set of skis, boots, and all the accessories. Literally about to go skiing tomorrow and thinking to myself, ‘I probably shouldn’t wear jeans under my snow pants…’ Their are also so many options online I was getting easily confused, this article really helped me figure out what I need in terms of gear and an underlayer. Thank you so much!

    • Christine

      Hey Mike,

      Happy to hear you found the article helpful! That’s always my goal, so you’re more than welcome. Hope you have fun out on the slopes this season, and never wear those jeans under your snowpants!

  • Denny D

    Just a note of thanks for some great info and very helpful with all the new tech clothing nowadays. Thanks again for the info.

    • Christine

      Hi Denny,

      Appreciate the feedback, and I’m glad you found this article helpful. Cheers to a great winter season!