Mom Goes Camping

Best Women’s Long Underwear and Base Layer Bottoms

best base layer bottoms for women

Women’s long underwear (aka long johns, thermal underwear or base layer bottoms) have come a long way.  Not only are there some really cool designs available, but there are long johns with high-tech features like being able to wick moisture away from your body and having panels for a perfect fit – great if you are tired of seams riding up your privates! :p

Here are the best women’s long underwear, including picks for intense outdoor activities, ones which can be worn as leggings and budget-friendly options.

Also read: Best Merino Base Layer Tops for Women


Quick Picks:


1. Icebreaker Bodyfit Oasis Women’s Merino Bottoms

icebreaker oasis womens long john base layers


  • Material: 100% Merino wool
  • Weight: Light/midweight (200g)
  • Waist: Low with elastic waistband
  • Colors: Black, gray, navy, espresso
  • Crotch gusset: Yes
  • Available At: Amazon, REI, Backcountry

Icebreaker clothing is expensive, but it’s pricy for a reason.  For starters, they use a really nice quality Merino wool.  The fibers range from 15.5 – 23.5  microns in size, which means they are so small that the wool is soft and not itchy.   Icebreaker wool is responsibly-sourced.

The construction on the Oasis leggings is also nice.  You can’t feel the seams at all.  There’s an additional fabric panel in the back area so the leggings won’t ride up on you at all.  The waistband is thinner (which I personally prefer).  However, the thinner waistband can dig into your waist, especially if you are a bit heavier.

At 200 g/m2, the Oasis leggings fall between a lightweight and mid base layer.  This weight is perfect for everyday wear, light activity in moderate weather, or high activity in colder weather.

Note: Icebreaker also makes a ¾ version of the Oasis leggings.


  • Super-fine Merino wool
  • Good fit
  • Also available in ¾ length


  • Thin waistband
  • Slightly see-through


2. Helly Hansen Midweight Lifa Merino

helly hansen base layer bottom womens front and back view

  • Material: 57% merino, 43% Lifa polypropylene
  • Weight: Midweight
  • Waist: High
  • Colors: Lots of color options plus patterns
  • Crotch gusset: Yes
  • Available At: Amazon, REI, Backcountry

These base layer bottoms are made from two layers.  The inner layer is trademarked Lifa material, which has superior wicking properties.  The exterior layer is Merino wool, which also helps with wicking and prevents odor.  This combination makes the bottoms perfect for cold-weather activities where you will be sweating a lot.

The bottoms are also constructed for high-intensity activities.  The crotch gusset is larger than on most women’s long johns, so you can practically do the splits in these without stretching them out.  The bootie and legs also have articulated patterns for movement and better fit.  You won’t feel the seams at all.

These are still a relatively new product, so there aren’t too many reviews.  But I suspect they will be popular with female adventurers.


  • Amazing fit
  • Very durable
  • Great wicking properties
  • Lots of colors and fun patterns
  • Not see-through


  • Hand-wash only


3. Icebreaker 250 Vertex Base Layer Bottoms

icebreaker vertex womens long johns front and back view

  • Material: 100% Merino wool
  • Weight: Midweight (250g)
  • Waist: Low with elastic waistband
  • Colors: Several patterns
  • Crotch gusset: Yes
  • Available At: Amazon, REI, Backcountry

The Vertex leggings by Icebreaker are similar to the Oasis ones. Both are made from super-fine Merino wool with an articulated construction. The difference is that the Vertex long johns are made from 250g wool, so are better suited for colder temps.  You can also wear them by themselves as leggings. They come in several cool patterned designs.


  • Super-fine Merino wool
  • Good fit
  • Nice patterned designs
  • Not see-through


  • Pricy
  • Thin waistband


4. Smartwool Classic 250 Baselayer Bottom

smartwool base layer bottoms classic front and back view

  • Material: 100% Merino
  • Weight: Midweight
  • Waist: Mid
  • Colors: Lots of color options plus patterns
  • Crotch gusset: Yes
  • Available At: Amazon, REI, Backcountry

These long johns are similar to the Icebreaker Vertex leggings.  Both are made from 250g Merino wool and have articulated designs for good movement. These Smartwool bottoms have a higher waist with a thicker waistband though.  The crotch area is a bit short though. If you have a larger bootie, they might not be the best choice.

Icebreaker products are generally better quality than Smartwool.  However, the difference in quality isn’t that huge – especially when you factor in that Smartwool products are usually a bit cheaper than Icebreaker. They also have more color and pattern options.


  • Good value
  • Not see-through


  • Crotch area a bit short
  • Not for large booties


5. Arc’teryx Rho Merino Base Layer Bottom

arcteryx rho base layer bottom

  • Material: 240g Merino wool, 220g Chira synthetic
  • Weight: Light/midweight
  • Waist: High with knit-lined waistband
  • Colors: Black, blue, sandstone
  • Crotch gusset: Yes
  • Available At: Amazon, REI

If you need a base layer for high-intensity activities – and are willing to pay more for them – then the Arc’teryx Rho leggings are fantastic.  Whereas other good long johns will maybe have a crotch gusset, the Rho leggings have a completely articulated design.  They are made up of several pieces of fabric which allow movement in all directions. Not only does this make them more comfortable, but it means they will last longer since they won’t stretch out in key areas.

The main material is 240g Merino wool, but they also contain Arc’teryxs trademarked Chira material which is high-wicking. There’s a pocket on the thigh, which is somewhat pointless IMO. It’s big enough to fit a phone.

Note: The leggings are slightly see-through! Don’t plan on wearing them with nothing on top! 🙂


  • Insanely good fit
  • Great wicking properties


  • Somewhat see-through
  • Pricy


6. REI Merino 185 Base Layer Bottoms

rei merino base layer bottoms

  • Material: 185g Merino wool
  • Weight: Lightweight
  • Waist: Low
  • Colors: Black, blue, purple
  • Crotch gusset: Yes
  • Available At: REI

REI’s Merino base layer bottoms are definitely more affordable than other brands.  However, be warned that these are 185g Merino – which is pretty lightweight.  Since there are no synthetics in the long johns (which would add strength), the bottoms can quickly get holes or tears.  This is fine if you need base layers for everyday wear or moderate activity.  But they aren’t a good choice if you do high-movement activities like climbing.

Considering that they are lightweight, the REI base layer bottoms are surprisingly not see-through. You can wear them as leggings.  But, over time, I’m guessing they will become somewhat transparent.

I also don’t like the stitching on these as much as Icebreaker long johns, but that’s just me be nitpicky – especially since the REI bottoms are cheaper.


  • Good value
  • Ultra-soft Merino
  • Not see-through


  • Not very durable


7. Kari Traa Floke Base Layer Bottoms

kari traa floke base layer bottoms

  • Material: 60% Merino, 40% Lenzing modal
  • Weight: Light/mid
  • Waist: Low
  • Colors: Multiple patterns
  • Crotch gusset: No
  • Available At: Amazon, REI, Backcountry

I found these base layer bottoms at a secondhand store and love them.  They are made up of a blend of Merino wool and “Lenzing modal”, which is a sustainably-made synthetic made by a German brand.  It’s very soft, breathable and has good wicking properties.

They are definitely more comfortable than some of the 100% Merino base layers I have but still don’t get me sweaty or stinky. You can’t feel the seams at all.  The waistband is very thin and low compared to most other women’s base layer bottoms. There isn’t a crotch gusset but the extra panel on the side does help with movement.

Because they are so comfy, I usually wear them as camping pajamas.  I also find the design to be perfect for pajamas.  But it’s a bit cheesy to wear as leggings IMO.

Considering that these were secondhand when I got them and I’ve washed them several times, they’ve held up well; no holes or tears yet.  Kari Traa products are fairly pricy but you can often find them on sale for very cheap, such as in the REI Outlet section.

Note: Kari Traa also makes a synthetic version of these bottoms called the Lune.


  • Great breathability
  • Very soft
  • Good value
  • Durable


  • No crotch gusset
  • Often on sale


8. Stoic Midweight Base Layer (Last Season’s)

stoic base layer bottoms womens long johns

  • Material: 85% polyester, 15% spandex
  • Weight: Midweight
  • Waist: Mid
  • Colors: Black, green, red, purple
  • Crotch gusset: Yes
  • Available At: Amazon, Backcountry

The brand Stoic isn’t very well known in the United States (it’s more popular in the UK and EU).  Their products aren’t fantastic, but they are a lot better than the generic stuff you’ll find online.   As of writing, you can find their last-season’s base layer bottoms on sale for stupidly cheap.

Since there is 15% spandex in these bottoms, you can expect them to stretch nicely.  There’s also an ample crotch gusset and articulated pattern around the waist/bootie area.  Of course, polyester and spandex will start to stink really quickly. This isn’t a problem with the Stoic bottoms themselves but rather a problem with all synthetic long johns.  The main issue is that the synthetic material wraps around the waistband, so it ends up being very chunky  and possibly uncomfortable.


  • Good stretch and fit
  • Can find on sale for very cheap


  • Waistband a bit bulky



Icebreaker Oasis$$$$Light/mid100% MerinoLowYesBlack, gray, navy, espresso
Helly Hansen Lifa Merino$$$Mid57% Merino, 43% LifaHighYesLots of colors and patterns
Icebreaker Vertex$$$$Mid100% MerinoLowYesSeveral patterns
Smartwool Classic$$$$Mid100% MerinoLowYesLots of colors and patterns
Arc'teryx Rho$$$$Light/midMerino and ChiraHighYesBlack, blue, sandstone
REI 185$$$Light 100% MerinoLowYesBlack, blue, purple
Kari Traa Floke$$Light/mid60% Merino, 40% Lenzing modalLowNoSeveral patterns
Stoic Mid$Mid85% polyester, 15% spandexLowYesBlack, green, red, purple


How to Choose Women’s Long Johns


The first thing to look at is the material of the long johns.

  • Cotton: Unless you are only using them as pajamas, don’t ever get cotton long johns. They absorb sweat, leaving you feeling cold.
  • Synthetics: Synthetics do a good job of wicking sweat away from your body so you don’t feel cold. They  start to stink really quickly though, so aren’t great for multi-day adventures where you can’t do laundry.
  • Wool: You really can’t do better than wool for long johns. It is warm, wicking, and doesn’t stink even after wearing it for days.   Merino wool is ultra-fine and doesn’t itch. The downsides are that wool is expensive, isn’t very durable, and needs to be washed carefully.
  • Synthetic/wool blends: Adding a bit of synthetic to wool base layers helps them be more durable and keep their shape better.

Also read: Is Merino Wool Worth It?



When talking about long johns and base layers, the “weight” refers to how warm they are.  With wool base layers, this is measured as grams of material per meter square: the higher the number, the thicker and warmer the garment will be.

Keep in mind that your legs don’t require as much insulation as your upper body.  You don’t want to end up sweaty! That’s why it’s hard to find heavyweight long johns: unless you are sitting outdoors sub-zero temps, they simply are too warm.

Most people skip a mid-layer on their legs (but still wear a mid-layer such as a fleece or puffy on their upper body).   If wearing an insulating layer on your legs or your shell pants have insulation, you’ll probably need to use a lighter base layer bottom then you have on your top.


  • Up to 200 g/m2
  • Best for light activity in mild temperatures or strenuous activity in colder temperatures
  • Thin fabric can tear quickly


  • 200 g/m2 to 300 g/m2
  • Good for light activity at cold temperatures or high activity in very cold temperatures
  • The most versatile option


  • 300 g/m2
  • Good for no/low activity during cold temperatures
  • Not good for moderate or high activity unless very cold temperatures
  • Usually can be worn by themselves as leggings


Crotch Gussets

A crotch gusset is a triangular piece of fabric.  It helps prevent the crotch area from stretching out, losing its shape or ripping.  This is important when doing outdoor activities like hiking or skiing.  Women’s long johns with crotch gussets are also more comfortable because you don’t have a seam going up your privates.


Articulated Construction

In addition to a crotch gusset, some womens base layer bottoms have articulated constructions.  This means they are made out of multiple panels of fabric which mimic your body’s movement.

Articulated base layers cost much more (because there are more fabric panels to sew together), but they are much more comfortable to wear.  They will (usually) also last longer because the construction prevents the material from stretching out.


High or Low-Rise Waist

This is a matter of personal preference.  Some people prefer a high-rise waist because they stay in place better, especially when bending over.  A high waist is usually better for bigger booties because you don’t have to worry about coverage as much.

I personally prefer a lower waist though.  I simply don’t like how waistbands feel when squeezing against my stomach.  It’s also easier to fit my other layers over low-waist long johns.


Waistband Thickness

You’ll also need to look at the thickness of the waistband.  Again, this is a matter of personal preference.  Some women prefer a thicker waistband because it keeps the long johns in place.  It usually won’t dig into your skin as much, which is important if you are a curvier woman.

Other women (myself included) prefer a very thin waistband since I don’t like the elastic feel against my skin.  I’m fairly skinny though, so I don’t have to worry about the waistband digging into my love handles.


Can You Wear them as Leggings?

Want to wear the base layer bottoms by themselves as leggings?  Be warned that some – especially lightweight Merino — are transparent.  Long johns also have a tendency to stretch/thin after repeated washings.  So, even if they start off as suitable for leggings, they might end up see-through later on.

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About the author /

Diane Vukovic grew up camping and backpacking in upstate New York. Now, she takes her own daughters on wilderness adventures so they can connect with nature and learn resiliency. With dozens of trips under her belt, Diane is an expert in minimalist camping, going lightweight, planning, and keeping her kids entertained without screens.

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