Merino Wool Rocks helps you find the merino wool clothes you need, whether to conquer the outdoors or find premium daily wear.

Best merino wool underwear for women

When travelling around the world, I use to have a pair of ExOfficio Undies. While I really loved both the look and how practically dried it would come out of the wash machine, they were not the best at wicking sweat and moisture while in Thailand or the Caribbean island! And because merino wool is highly insulating, they are the best to keep you warm when it’s cold.

If you are already familiar with merino wool underwear and just need to pick up the best of 2019, jump directly to our recommendations. If you feel like you need to dig a bit more before to commit and need a bit more guidance to understand what matters when it comes to choose the right underwear, have a closer look to our FAQ section just below. And if you have more questions, just leave one in the comments. We will be happy to help.

What to consider when choosing your merino wool underwear:

The main advantages of merino wool over synthetics ones for underwear garnement are the natural odor-prevention and antibacterial properties of the wool.

One way to reduce your chances of developing vaginitis, including yeast infections, is to choose underwear made of natural fibers. Because merino wool is so breathable (it allows the transfer of air and moisture), it is a superior material against heat and moisture, compared to synthetic such as polyester and nylon, which are usually treated to provide antimicrobial properties but they will, however, get washed out over time.

Basically, the breathability of merino wool will add a feeling of freshness to your undies which is not a luxury when sweat is inevitable, especially during the summer.

Underwears, especially when used for outdoors activities should be quick-drying. With merino wool, it is possible to wash your panties by hand in the evening and let them dry overnight. You basically only need 2 pairs if you go with the “wear one, wash one” principle.

There is always this statement than synthetic underwear dry faster than merino wool ones. We found than the difference is only of 60 to 90 minutes difference. The biggest advantage of the wool though is that you can wear it and it will dry on you very quickly without you feeling cold. Packing slightly wet synthetic underwears in you bag can have dramatic consequences in terms of smell and possible molding as the antimicrobial treatments will eventually get washed out.

The activity you are planning to wear these underwear for matters a lot. While they should always feel comfortable, you might not expect the same features if you are planning a short but high-impact activity, a long hike or a day lounging around.

Flatlock seams
This is particularly important for the layers that are the closest from the skin. It is crucial, especially for outdoor activities such as hiking or snowboarding, to avoid normal seams which tend to create some chafing and irritation of the skin by rubbing against it repeatedly. For example, we have carefully kept out of the selection panties which have a centre back seam. Yes, it helps shaped to fit your body but it will only be a matter of time before it starts irritating if you go hiking with them.

Support level for bra
The level of support you are looking for will depend of your activity (level of bounce) and breast size.
There are 2 ways for underwear garnements to bring support, that can be used independently or combined:
1) Have a tight-fitting elastic top pressing your breasts against your chest wall (compression).
2) Have an encapsulating method of each breast which better inhibit bounce. It is most commonly used for larger breast size.

One important feature that brings support is the band. The wider the band (over 2cm), the more support for your chest you will get.

The racer back is a very popular feature as the straps will not fall down over shoulders as you are moving. This extra security in the back also implies that the straps press the bra closer to the body and thus offer more support. On the other hand, some people find racer backs uncomfortable if they feel as though too much weight is being carried on the trapezius muscle rather than further out on the clavicle.

When reading comments, you might see some people reporting as if the straps dig into their shoulder and neck. It can happen when the bra is not tight enough and the weight of the breast isn’t close to you chest which means that more weight will rely on being supported by the straps. In that case, choose a bra that offers more coverage.

Make sure that your underwear are snug-fitting to enhance thermal efficiency and avoid chafing as well as irritation. It might therefore make sense to avoid thongs and models which do not offer coverage for long outdoor activities as you won’t beneficiate from the fabulous insulating property that merino wool is known for. Boyshort or even longer short are most popular among snowboarders who spend some time seating in the snow.

Sometimes added to sports bra for mobility purposes (to let you twist and turn) as well as sweat management when combined with a mesh fabric in high-sweat zones for ventilation

Some added lycra will help stretch and shape retention, especially on longer bottom wear to prevent them from becoming shaggy and starts rolling.

As opposite to mid or top layers garnements, underwear, especially panties need to be wash often. So durability is important and even if the price might seem a bit high, the quality of the wool will make the difference on the mid to long term here.

Thanks to the natural antimicrobial qualities of the wool, it is possible to get merino underwear quite clean just by hand-washing and drying them. If you are planning on using them for daily wear on the other hand, make sure to pick on on the list that is machine-washable – most of the ones reviewed are.

For long top and bottom thermal underwear, resist to your natural habit of washing them often. There was no need and hanging them in the sun can be as efficient as washing them!

Best bottom underwear

When considering the cut to go for, think of activities you will be doing. I wouldn’t recommend a thong for hiking for example, as it is likely to create some irritation over time. If you are planning on wearing them everyday, keep in mind a low waist will suits your casual pants better. And while the price tag might seem high, durability is important when it comes to undies and they need regular wash. We were careful to pick the best wool quality here as it makes the difference on the long term so it will be worthwhile the investment.
Here is our pick:

  • Fabric: 83% Australian Merino Wool | 12% Nylon | 5% Spandex
  • Fabric weight: 180g/m
  • Features: Forward set side seams (which is different than seamless!)
  • Price range (estimate): $26

With the touch of Spandex, these have been designed to move with you, so you can focus on your form. There are the perfect all-around and can be used both for training and for traveling.

See on WoolX website | Check on Amazon

Also great:

SmartWool Womens NTS Micro 150 in blue

SmartWool Womens NTS Micro 150 Pattern Bikini

  • Fabric: 100% merino wool
  • Care: Machine wash
  • Price range (estimate): $30

Similar cut than the one above but with a 100% merino wool fabric. Features include: tagless and flatlock seams (yay!) to reduce chafing and next-to-skin comfort. The crotch panel have been designed to let you (and your lady parts) breathe easy. Exists in many colors including some stripes pattern.

See on SmartWool’s site | Check price on Amazon

Icebreaker Merino Women’s Sprite Hot Pants in yellow

Best merino wool boyshort: Icebreaker Women’s Sprite Hot Pants

  • Material: 83% Merino Wool, 12% Nylon, 5% LYCRA
  • Fabric Weight: 150g/m (Ultralight)
  • Construction: Offset seams, best for daily wear
  • Care: Machine Wash
  • Price range (estimate): $30 – $40

If you want more coverage or generally finds that panties tend to ride up for you, this shape will suit you better. They look very sporty with the wide band. It is nice to make sure they don’t roll up and look flattering but think twice if you are also intend to wear another long baseyers in top of it with a similar wide waistband that lies flat against your skin. They have moved the “normal” side seam forward for comfort, but there are still seam. The Lycra really helps with shape retention and avoid the shaggy feel after a few hours of wear.

See on Icebreaker’s site | Check price on Amazon

Runner up:

Ridge Merino Wool Women's Ridge Boy Short in black

Ridge Merino Wool Women’s Boy Short

  • Fabric: 84% Merino Wool, 12% Nylon, 4% Spandex
  • Fabric weight: 180g
  • Features: Flatlocked seams and removable care label for max comfort
  • Price range (estimate): $30

Note that the wool weight is on the thicker side compared to some other bottom underwear. Ridge has iterated on the design of the original waist band after getting feedback and it is now one of the most popular boyshort among female backpackers. Exists in several colors.

See on Ridge’s site | Check price on Amazon

Icebreaker Merino Siren Thong in black

Best merino wool thong: Icebreaker Merino Siren Thong

  • Material: 83% Merino Wool, 12% Nylon, 5% LYCRA
  • Fabric Weight: 150g/m (Ultralight)
  • Construction: Offset seams
  • Best For: Daily wear, workout
  • Care: Machine Wash
  • Price range (estimate): $28

Thongs such as this won’t be ideal for any long outdoor activities as you won’t beneficiate from the insulating property of the merino wool and it will eventually end up to be irritating. That said this is the best cut if you want to keep your underwear invisible and therefore it is a very popular model for daily wear, casual travel or workout under a tight leggings or short.

See on Icebreaker | Check price on Amazon

Best sports bra

The real advantage for a merino wool bra’s no matter if it is to work out or to travel is that you can go a couple of days without washing it.

  • Fabric: 50 % Merino wool / 33 % TENCEL® / 12 % Nylon / 5 % LYCRA
  • Construction: Flat seams, mesh fabric, added cup
  • Care: Machine wash
  • Price range (estimate): $65

This is the most supportive merino wool bra on the market at the moment. I used to own one of the predecessors: The Rush, made of 100% merino which was incredibly odor resistant. The new model has some Tencel and Nylon for resistance as well as Lycra which helps for shape retention.

I am a size D and I find it good enough for my CrossFit training which typically include some running and weightlifting even if there is no elastic or support infrastructure as such. That fact means it wicks really well. To allow even better sweat management, they have added a mesh fabric placed in high-sweat zones for ventilation.

Caro wearing the Icebreacker Sports Bra

To prevent the ‘sports-bra-monoboob’ issue that can come with this type of bra, they have added cup inserts that contours to your shape. It is also convenient when travelling as you could use it as a spontaneous swimsuit if necessary as it won’t be see through in the darker colors.

See on Icebreaker’s website | Check price on Amazon

Also great:

Smartwool Seamless Racerback Sports Bra in Navy blue

Smartwool Seamless Racerback Sports Bra

  • Fabric: Inner Lining: 68% Merino Wool, 21% Nylon, 11% Elastane; Shell – 85% Nylon, 15% Elastane
  • Care: machine wash cold on a gentle cycle
  • Price range (estimate): $60

Good sports bra as well with straps that give you the option of a normal bra fit or cross over. Note that the outer layer is not made of merino wool but synthetic, which will also dry very fast.

See on SmartWool’s site | Check price on Amazon

Stella X-Back Bra from Mons Royale

Mons Royale Stella X-Back Bra

  • Fabric: 83% Merino Wool 13% Nylon 4% Elastane
  • Features: removable padding, crossed straps
  • Price estimate: $50 (the brand is based in the UK)

This bra offers low support with a elasticated under bust band, so a bit less support than the 2 above but still plenty for most activities such as yoga.
We like the fact that the straps with the open back that gives a great range of motion.

See on Mons Royale’s site | See on Amazon

Best everyday bra

Everyday bra: Icebreaker Merino Women’s Siren Bra

  • Material: 83% Merino Wool, 12% Nylon, 5% LYCRA
  • Fabric Weight: 150g/m (Ultralight)
  • Construction: No side seam construction, Adjustable straps
  • Best for: Daily wear, workout, A-B cup
  • Care: Machine Wash
  • Price range (estimate): $34.56 – $50.00

It looks more like a normal bra, minus the underwire. It is probably not good enough for running or burpees, especially for size C and above, but it is comfortable enough for daily wear and yoga type of activity. It comes with removable cups (if you don’t want nipples to show through) and adjustable straps which can be a plus for some.

See on Icebreaker | Check price on Amazon

Also great:

Stay GLDN Essential Bralette in black

Stay GLDN The Essential Bralette

  • Fabric: 81% Merino wool, 14% Nylon, 5% Spandex
  • Features: Adjustable straps that can be worn crossed or uncrossed, flat seams
  • Care: Machine washable
  • Price estimate: $30

Simple daily bra that aims at maximum comfort. It has a two inch wide band for support, no tag and flat seams.

See on Stay GLDN’s site

Best long underwear bottoms

Best Merino Wool Tights: Wolford’s Merino Wool Tights

  • Material: 49% virgin wool, 49% nylon, 2% elastane (in waistband)
  • Fabric Weight: 150g/m (Ultralight)
  • Construction: Flat seams, reinforcement on the sole
  • Care: Machine Wash, 30°C on a gentle cycle
  • Price range (estimate): $55 – $80.00

Very high quality tights with flat seams and some reinforcement under the foot, both at the toe and heel. Available in several colours.

See on Wolford | Check price on Amazon

Also great and good value:

Janus Wool Tights in black

Janus Wool Tights Made in Norway

  • Fabric: 68% Wool 32% Polyamide 2% Elastane
  • Care: machine wash (85 F degrees)
  • Price range (estimate): $32

These are great if you are looking for a jacquard more elaborated pattern. Also available in off-white as well.

Check price on Amazon

If you are looking for a pair of long bottom baselayer, read our in-depth review of 15 pairs of merino wool leggings here, ordered based on fabric weight and activity type. We can also check our recommendation for undershirts and camisoles here.

4 responses to “Best merino wool underwear for women

  1. Sadly Ibex went out of business leaving many fans of their balance briefs bereft. I finally found a comfortable, well made panty and now I can’t find it in my size anymore.
    A number of online reviewers commented that Smartwool’s Phd’s ride up into wedgies.
    What’s a gal to do?

    1. Try bamboo undies, we love the Boody range available online in a variety of shapes and sizes and in three colour options. I’m a size 12 or M being 96cm bust, 78 cm waist and 98 cm hips and I buy the medium from Boody though the midi briefs are a little large around the leg opening and aren’t as comfy as the classic bikini brief of which I own several, likewise I think I’m between sizes in the full brief as my legs are quite slim, so the leg opening is a little large but the full brief is still comfy I could probably go down a size. I wash the Boody underwear in a liquid detergent which is safe for woollens and safer for the environment and they look as if they are new. I never tumble dry them, just line dry.

    2. Some other options that might work (harder to obtain if you live in the US, but they are around online):
      – Mons Royale FOLO or Everyday Brief (I love their merino, super soft, lasts a long time for what I put it through)
      -Merino Country hipster briefs (a good replacement for smartwool hipster brief which smartwool no longer makes)
      -Icebreaker Siren Bikini (these are thinner than most, which can be good or bad depending on what you like or need it for)
      -Finisterre Pali Pant (50% merino, 50% tencel)

  2. Merino 33 briefs are another good option. They are a small company based out of NH, and although I’ve never tried their briefs, their long underwear is great quality.

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