Do You Wear Underwear Under Long Johns?

Do you wear underwear under your long johns or go commando? It’s a question we’re sure many of you have wondered about at one point or another. Well, wonder no more.

We’ve got the answer in this article that talks about if it’s okay to wear underwear under long johns and why some people find it uncomfortable.

They go by many names, thermal underwear (thermals), base layer, long underwear, or simply “long johns.” The bottom line is they are a winter wardrobe essential.

Thermal underwear is made from different materials like wool, silk, or synthetic fibers. It works to keep you warm by trapping air close to your skin. They are meant to be worn tight to the skin for maximum effectiveness.

We will get into all of this more.

What Is Thermal Underwear?

Thermals are a type of underwear that helps wick moisture away from your body and help you keep warm. Long johns work much better than other types of loose-fitting clothing because their tight-fitting design traps air close to your skin, which provides insulation.

In addition, long johns paired with outer layers work wonders to keep you cozy and warm in cold weather.

Thermal undies can be worn separately as tops and bottoms or together to cover you from neck to ankle.

Why Should You Wear Underwear With Your Thermals?

When you wear thermals, you have a protective and comfortable layer underneath. Although many people think underwear can hinder heat insulation, this is not true.

At any rate, make sure you put something on before putting on those thermals. But first, let’s talk about good reasons to put on your underwear and thermals.

Wear Your Thermals Longer Without Washing

Suppose you’re wearing thermals and underwear together. In that case, you can wear thermals for a longer period before washing them.

This is because the underwear will help protect the thermals from getting dirty and keep you more comfortable.

For example, if you are on days-long backpacking trips, pack as lightly as possible. In addition, underwear is easier to change than taking multiple pairs of long johns with you.

You can get away with one pair of thermals and change your underwear along the way. This way, you can keep clean where you need it most (remember that hygiene is still essential outdoors) and still wear your long johns.

Long Johns Can Serve as an Outer Layer

When the temperature drops, it’s essential to start dressing in layers to keep yourself warm. One of the most important layers to have is thermal underwear.

Thermal underwear can be worn as an underlayer to keep you warm, or it can also be worn as an outer layer when the weather warms up.

So, when the weather warms up, you can cool off by stripping down to your base layer. Since thermals are very revealing, your friends will probably appreciate that you have underwear on.

Change on the Fly

Thermals are a great way to stay warm in cold weather. But if you are on a long trip, they will get dirty, and eventually, you need to swap them out for a new pair.

Or, you may need to change into different clothes if the weather warms up quickly. However, this process becomes much more manageable if you wear underwear with your thermals.

All you have to do is remove your thermals and swap them out for fresh ones or different clothing.

No Chafing

Long johns are designed to fit snugly, but sometimes they might rub against your skin in undesirable areas. Wearing a pair of underwear can save you the unpleasant feeling of chafing.

Why Not Wear Underwear With Thermals?

There are a couple of issues to consider if you wear underpants with your long johns.

The problem with wearing thermal underwear and underwear together is that thermals are made for tight-fitting design. So the underwear can bunch up (a little uncomfy) when worn underneath this kind of clothing.

Also, one extra layer can make it harder to get all of your undies off to go to the bathroom (especially if you are in a hurry).

When Should You Wear Long Johns?

Thermal underwear is a great way to keep your body warm and can be worn in various settings.

Some examples include:

  • Wearing thermal underwear when you go camping in cold weather to help you stay warm
  • You can wear thermal underwear as pajamas at night to keep your body warm
  • Wear long johns under other clothing when it’s cold outside
  • As a base layer to protect you from the cold anytime you want

Types of Thermals

Thermal underwear comes in various weights, differentiated by their names- lightweight, mediumweight, and heavyweight.

The different weights provide different insulation levels depending on the climate and weather conditions.

For example, suppose you are camping in cold weather (below freezing temperatures). In that case, you will need to pack heavyweight thermal underwear.

This weight will provide the most insulation and protection from the cold weather.

However, suppose you will just be wearing your thermal underwear around the house. In that case, you can get away with lightweight thermals.

These thermals will provide minimal insulation but are much more comfortable and less bulky to wear.

Medium-weight thermals are a good in-between choice.

What to Wear Over Long Johns

Now that you have your base layer set, what you wear over thermals depends on the conditions and what you are doing.

Dressing in layers is the best way to approach your outdoor adventure. This way, you can easily adjust as temperatures change.

If the conditions are calm, you can wear a light jacket which is excellent for less extreme weather conditions.

In more extreme weather, a heavy fleece, hoodie, or both might be needed for extra warmth and protection from the cold and windy conditions. Consider a windbreaker or other shell on top of a hoodie or fleece in wet or windy conditions.

For bottoms, you can wear sweatpants for sleeping. You might consider running, hiking, or fleece-lined pants when doing activities during the day.

Many of the pants available today are quick drying or have an outer shell similar to a windbreaker to repel wet or windy conditions.

Don’t Forget About Accessories

You will need good boots and socks to keep your feet warm and protected.

You should consider Merino wool socks if you are in the market for a good pair of socks to keep your feet warm during cold weather.

This type of wool is very soft and retains heat well, making it a perfect material for socks.

Merino wool is also known for being moisture-wicking, which will help keep your feet dry even if they get wet.

If the conditions dictate, gloves and a beanie will round out your wardrobe.

At the end of the day, it depends on the conditions as to how many layers you will need. You don’t want to be Randy from “A Christmas Story .”You want to be able to move freely.

How to Choose the Best Long Johns

Different kinds of long johns include synthetic, wool, and silk. Thermals need to do an excellent job of wicking moisture, which helps keep you dry and warm.


Silk works well as a base layer, depending on your activity. The downsides of silk are that it doesn’t wick moisture and other materials, and it will retain more odor, meaning it needs to be washed more often.

The benefits of silk thermals are that other layers slip over easily and are pretty lightweight.

Silk is a good option if you go out for an easy hike on a cool spring or fall day.


Merino wool is an excellent material for thermals. Long gone are the days of traditional cotton long johns from years past. Merino wool can be woven with other fabrics to be ultrafine and flexible.

Merino wool has many characteristics that make it an excellent material for thermals. It’s cool, wicks moisture, is odor-free (yay!), and is durable.


Synthetic materials like polyester are used in long johns because they are durable and can wick away moisture. This makes it a good choice for clothing that needs to be lightweight and moisture-wicking.

You might know synthetics as rayon or other blended fabrics. Synthetic materials are excellent for thermals because they wick moisture and are durable. They do retain some odor, but not compared to other materials.


Can You Wear Long Johns Camping?

Absolutely! When you are camping, you need to be prepared for all types of weather. This means you must have the proper clothing to keep you warm and dry.

Long johns are a great way to keep your legs and body warm, and they are also lightweight and easy to pack.

Do You Wear Boxers Underneath Long Johns?

Thermals fit tight, so wearing boxers under long johns is not a great idea because the fabric can bunch up and cause discomfort.

Can You Wear Thermals Without Underwear?

Of course, you can wear thermals without underwear. Still, hopefully, after reading this blog post, you will understand the many benefits of wearing underwear with long johns.


There are many benefits to wearing underwear under long johns, including cleanliness and changing quickly when the conditions require it.

Wearing underwear with long johns does not impede the benefits of wearing thermals, so don’t worry about that.

The benefits of wearing underwear under long johns outweigh any downside (mainly bunching).

Let us know if you have any questions or comments below.

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Steve Morrow owns Paddle About, an outdoor recreation and travel blog. Steve loves to travel, kayak, paddle board, camp, hike, and spend time outdoors with his wife and two kids. When he's not exploring the great outdoors, Steve enjoys writing about his adventures and sharing tips for getting the most out of your outdoor experiences. He has a lot of interesting stories to share, and he's always happy to help others get more out of life.

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About the author
Steve Morrow
Steve Morrow owns Paddle About, an outdoor recreation and travel blog. Steve loves to travel, kayak, paddle board, camp, hike, and spend time outdoors with his wife and two kids. When he's not exploring the great outdoors, Steve enjoys writing about his adventures and sharing tips for getting the most out of your outdoor experiences. He has a lot of interesting stories to share, and he's always happy to help others get more out of life.