BEST WOMEN’S HIKING UNDERWEAR OF 2019
The Short Version:
Best Women’s Merino Briefs: Smartwool Merino 150 Bikini
Best Women’s Synthetic Briefs: ExOfficio Give-N-Go Sport Mesh Bikini
The Long Version:
“Hiking gear starts with your underwear”.
It’s not the slogan of our new hiking underwear brand. It’s just a fact.
When setting up for a hike or backpacking trip, the first item to attach itself to you will be your underwear. It goes on before any of your other worn clothing (ideally anyway), and before any of the carried gear in your pack.
Because your underwear is a next-to-skin baselayer, it needs to function well. It should be breathable, moisture-wicking, fast-drying, and — ideally — it should not feel damp or cold when wet.
And, not all underwear are created equal.
Materials commonly used to make your city clothes — in particular, cotton — do not perform well during active use or in cold and wet environments. Cotton absorbs water, after which it is heavy, slow drying, and does not insulate. So during active use — when you are likely to be sweating — cotton is the last thing you want against your skin.
So if not cotton, what else?
There are various materials and styles used for hiking underwear, but suffice to say that the two most popular materials are merino wool and synthetics. If you are not familiar with the benefits of merino wool or synthetic fibers used in hiking underwear, then check out our buying advice at the bottom of the page.
Otherwise, let’s just jump straight into it.
Here is our list of the best women’s hiking underwear. These high performing undies will have you travelling comfortable all day long, so that you can focus on the more important task of getting up that mountain!
If you love this list of the best women’s hiking underwear, then you'll likely love reading some of our other gear-fiend related pages:
MATERIALS: 87% merino wool, 13% nylon
PROS: Comfortable fit, High quality merino, Lightweight
CONS: Odour resistant
BEST FOR: Those who want the best merino briefs
MRRP: US $30
At Ultimate Gear Lists we love merino! It is a natural fiber with amazing properties that make it the perfect material for active use clothing… it is naturally odour-resistant, moisture-wicking, insulates when wet, and dries fast. It is soft and comfortable against the skin (at least good quality merino is). And these undies possess all of those fine qualities
The Smartwool Merino 150 Bikini briefs are a lightweight underwear perfect for hiking, backpacking and other active use.
It’s often suggested that merino is too warm and not ideal for warm weather, but we don’t believe that to be the case. In all but the absolute hottest weather, we hike in merino underwear and t-shirt. These underwear are lightweight and breathable, and best yet they are still comfortable even when you are sweating it out on the climb up the mountain!
And they are fast drying even at the end of the day, or if you need to wash them on a multi-day trip.
The Smartwool 150 Merino Bikini may not be quite as durable as some of the synthetic underwear listed below, but we think they are durable enough. They will last long enough to earn their dues. Granted, they may not be the cheapest underwear on the shelf. And at $30, they may well be amongst the most expensive. But at Ultimate Gear Lists, we feel the price tag for these undies is justified by their performance.
MATERIALS: 83% merino wool, 12% nylon, 5% spandex
PROS: Comfortable fit for most, High quality merino, Naturally odour-resistant
BEST FOR: Those with a smaller rear or who prefer a narrower bikini
MRRP: US $30
Another top contender for best merino undies are the Icebreaker Siren Bikini. These undies are comfortable, breathable, and lightweight.
The cut of the Icebreaker Siren Bikini is a little narrower, so if you are looking for a good amount of coverage to the rear, then perhaps look elsewhere. But, if you have a smaller rear, or are usually comfortable in a slightly narrower bikini then these are ideal.
The main materials for the Icebreaker Siren Bikini are almost identical to the Smartwool Merino 150 Bikini. They both use a 150-weight (i.e. lightweight) merino fabric wrapped around a nylon core. Both companies refer to this material as their “corespun” fabric. The corespun fabric provides the next-to-skin comfort of merino wool, and retains it’s odour-resistant properties, but the nylon core increases durability.
MATERIALS: 93% nylon, 7% spandex
PROS: Soft material, Comfortable, Breathable, Fast drying
BEST FOR: Active and all-purpose use, Those who don’t want merino
MRRP: US $24
The ExOfficio Give-N-Go Sport Mesh Bikini stands out from the pack when it comes to synthetic hiking underwear.
The synthetic mesh used on these briefs is surprisingly soft and highly breathable.
The Give-N-Go Sport Mesh material is perfect for both high-intensity activities and general purpose everyday use. Whether you’re scaling the top of Mt Rainier, or just bike riding across Treptower Park in Berlin, these undies will have you comfortable in the driving seat. And another plus of the breathable mesh is that it is fast drying.
ExOfficio use flatlock seams throughout, but if you prefer synthetic bikini brief with smaller seams around the thighs, then perhaps consider the Patagonia Barely Hipster instead.
If you’d prefer a bit more coverage to the rear, then check out the ExOfficio Give-N-Go Sport Mesh Hipkini. It uses the exact same materials as the bikini brief — and performs just as well — but it has a slightly different cut with a little more coverage on the hip and rear.
MATERIALS: 89% nylon (66% recycled), 11% spandex
CUT: Hipster bikini
PROS: Comfortable, Breathable, Fast drying, Lightweight
BEST FOR: Active and all-purpose use, Those who find seams irritating
MRRP: US $22
When you’re on a multi-day backpacking trip, every ounce of carried clothing needs to be justified. So, an obvious place to start cutting a few grams is in the areas where insulating materials aren’t required!
If you’re looking for a lightweight pair of synthetic underwear that still ticks all the boxes, then the Patagonia Barely Hipster could be just the pick. Overall, we tend to prefer the mesh used on the ExOfficio Give-N-Go Mesh Sport offering, but to be honest, there isn’t much in it.
If you are after a synthetic bikini brief for high-intensity activities, then the Patagonia Barely Hipster is still a great choice.
The thigh seams on this pair of undies are also far more minimal than on the Patagonia Active Briefs or the ExOfficio offering. We find that all of the underwear on our list are pretty good at staying put and not riding up during activity, but these undies may be a good choice if you prefer a design with minimalist seams.
Like many of Patagonia’s products, these undies are made primarily from recycled materials — namely recycled polyester — so you also get the added benefit of buying from a company that takes it’s environmental footprint very seriously. These undies will not only be good for you, but also just that little bit better for our precious earth.
MATERIALS: 88% nylon (55% recycled), 12% spandex
PROS: Full coverage, Wide waistband
BEST FOR: Those who want a full brief
MRRP: US $24
If you are looking for a synthetic full brief for active use, then the Patagonia Active Briefs are likely to be just what you are looking for.
These briefs have a much wider waistband and provide much fuller coverage than the other undies in our list. Patagonia have used flatlock seams throughout though, so you won’t find the wider waistband or wider seams on these undies irritating. However, be wary that higher-waist underwear can sometimes rub on your lower back, under the pressure of your backpack. So if you plan to wear them hiking, then maybe check out the positioning of the lower part of the waist belt on your backpack to see whether this could be an issue for you.
These undies are made from a partly recycled nylon similar to that used on the Patagonia Barely Hipster. The moisture-wicking properties of the material performs well. However — at 4.8 ounces per square yard — the material used on these briefs is slightly thicker than the 3.9 oz material used on the Barely Hipster and so they don’t dry quite as fast when wet.
The other downside (although only a small one) is that, at around 1.15 oz (33 grams), these undies are the heaviest on our list. The Patagonia Barely Hipster — at 0.7 oz (20 grams) — is a much lighter choice in the synthetic range, and the Smartwool Merino 150 — at 0.7 oz (20 grams) — is a much lighter choice in the merino range. However, these weight differences are only really an issue if you are travelling, or on a multiday backpacking trip, where you might be aiming to minimise the weight your pack.
And in any case the potential weight savings you can make by choosing lighter undies are tiny relative to the big four items you are going to be carrying when backpacking, namely your backpack, tent, sleeping bag, and sleeping pad.
First and foremost, choose your undies based on comfort and performance. These are your two most important criteria. And for a synthetic full brief, the Patagonia Active Briefs tick both those boxes.
For the most part, there are two possible choices when it comes to materials for hiking underwear. The first is merino wool, a natural fiber. The second is synthetic fibers, primarily nylon or polyester.
Both merino and synthetic materials have pros and cons. If you are interested in reading about them in more detail, then check out our article Merino vs Synthetic: The Baselayer Wars.
In brief though, both have great moisture-wicking properties, are quick drying, and will keep you insulated when wet.
The upside of merino is that it is soft, naturally odour-resistant, and feels nicer against the skin when damp. The downside of merino is that it is expensive and less durable.
The upside of synthetics are that they are less expensive and more durable. But the downside is that they aren’t as soft as merino and — although they dry slightly faster than merino — they don’t feel particularly nice against the skin when wet.
Whether you opt for merino or synthetic underwear will depend on: your budget, your demands for durability, and your personal preferences (some people just really love merino, others just really love synthetics… personally we are the former). In some cases, manufacturers will use a blend — for example, merino wool wrapped around a synthetic nylon core — like in the Smartwool and Icebreaker undies reviewed above. This can lead to the best of worlds, since you get the benefits of merino against the skin, but the added durability of the synthetics.
This is entirely a personal choice, and you will probably know better than us what you prefer. But for most women, a slightly more fitted pair of underwear — such as a bikini brief — will ride up less, and is less likely to bunch, get caught under your backpack, or chaff while hiking.
When it comes to design, always choose underwear than have flatlock seams. This will help to prevent chaffing. If possible, you also want to avoid any seams in places that may rub under the pressure of your backpack. For example, high-cut underwear can cause irritation if the lower part of your backpack is rubbing on the waistband.
Similarly, a seam or label at the centre-back of the waistband can be irritating if your backpack is rubbing on it. For most women, a lower-cut brief will be more comfortable for hiking.
Merino wool is naturally odour-resistant, so if you opt for merino undies then that will just be an added benefit of the part and parcel.
Unfortunately, synthetics don’t offer the same perks. Some manufacturers treat synthetic fibers with an antimicrobial coating to increase odour-resistance, so that is something you may want to look out for. However, antimicrobial treatments usually don’t live up to their promises, and they will fade after repeated washing anyway. So don’t let that be a big sway factor in your decision.
Ideally you want underwear that will be durable. But durability is an area you may need to consider a trade-off. Synthetics are likely to be more durable than merino wool, so you need to simply decide which factors are most important to you.
When it comes to washing, merino wool requires slightly more care than synthetics. But the amount of care required is sometimes overrated. In most instances, you can throw your merino underwear in the wash with your other clothes, just try to be sensible and be sure to avoid excessive heat. Ideally, wash them using cold or warm water, and usually with a medium spin, rather than trying to thrash them to shreds using a fast spin cycle.
Due to it’s odour-resistant properties, merino doesn’t need to be washed as often as synthetic either, so try to only wash your merino garments when they actually need it. It will prolong their lifetime.
You can even throw good quality merino in the dryer, if you really need to. Just be sure to keep the temperature on low! A hot dryer cycle will leave you with a pair of underwear five sizes too small. Although, it is always better to air-dry your garments if possible. Both synthetic and merino dry pretty fast, so if you have a day to spare — or even just a few hours in the sun —then aim to just dry them naturally. Although, avoid direct sunlight if it is very hot, and don’t hang garments if they are very wet (they might stretch! — although undies should usually be ok).
Having said all that, here is our disclaimer: “always follow the manufacturer’s care instructions shown on the label” (sort of…).