Best Men’s Hiking Underwear of 2019


The Short Version:

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 (assuming you are planning on wearing some). And 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 men’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 men’s hiking underwear, then you'll likely love reading some of our other gear-fiend related pages:

MATERIALS: 87% merino wool, 13% nylon

CUT: Boxer brief

PROS: Comfortable fit, Flat-lock seams, Lightweight, Quick drying

CONS: Expensive

BEST FOR: Those who want the best merino boxers around

PRICE: $$$

Without a doubt Smartwool make some of the best baselayers for hiking, backpacking, and travelling. Their merino is comfortable against the skin, their fits are slim but relaxed, and — perhaps best of all — their garments are extremely durable for merino. And these Smartwool boxers are no exception.

The Smartwool Merino 150 Boxer Briefs are, hands down, our favourite boxers to wear hiking and backpacking.

These merino boxers use a slim fit that will be suitable for most, but also allow some breathing room so that your special parts can catch some air when you’re working up a sweat on the trail. The airy fit is also ideal for multi-day backpacking trips where — let’s be honest — we might not have a fresh pair of gruts to chuck on each morning.

Even better, Smartwool use flatlock seams throughout, which helps to minimise any chance of chaffing. They also use a merino lined, and wide, waistband. This design means that the waistband won’t rub and irritate your lower back under the weight of your pack, like the waistband on many boxers can.

You of course have the added benefits of merino wool — namely, that it is far more odour-resistant than synthetic, and that it doesn’t feel too bad when damp. These boxers also dry relatively fast. Much faster than cotton, and about as fast as a synthetic polyester or nylon (discussed more in our buying advice below).

While many people have reservations about the durability of merino products, we’ve found the Smartwool Merino 150 Boxers to be very durable. In general, we’ve found Smartwool’s merino baselayers to be far more durable than many other manufacturers’ merino baselayers. What's more is that Smartwool now use a nylon core with merino wound around it. This increases durability but retains the benefits of merino against the skin.

The default design is plain black. But if you’re feeling wild, they also come in a range of other colours or fancy prints.

Granted, these boxers aren’t exactly cheap. In fact they are pretty f**king expensive. But, then again, we aren’t suggesting that you buy these as your everyday boxers to wear day in and day out as you stomp the pavements of the inner city. Although if your budget allows, they will perform equally well in that environment! Rather, these boxers are designed for the trail. And that is where they really perform.

MATERIALS: 87% merino wool, 12% nylon, 5% lycra

CUT: Boxer brief

PROS: Comfortable fit, Flat-lock seams

CONS: Expensive

BEST FOR: Loyal Icebreaker junkies

PRICE: $$$

The headline competitor to Smartwool, New Zealand’s Icebreaker is one of the most popular manufacturers of merino clothing. And their main offering in the men’s underwear category doesn’t disappoint.

The Icebreaker Anatomica Boxer Briefs are a quality pair of merino underwear. With flatlock seams, open fly, relatively snug fit, and comfortable waistband these boxers are pretty much on par with our top pick the Smartwool Merino 150 Boxer Briefs.

Both manufacturers use an ultralight and breathable 150-weight merino perfect for underwear. They also both use corespun merino (with a nylon core to increase durability). This helps to increase durability, but even with a nylon core, merino boxers are still going to be more fragile than purely synthetic (e.g. nylon or polyester) boxers. Nonetheless, we think the benefits of merino outweighs its downsides.

We chose the Smartwool offering as our top pick since the merino lined waistband is more comfortable. But, to be honest, there isn’t much in it… both the Icebreaker and Smartwool boxer briefs reviewed here are top performers.

MATERIALS: 92% nylon, 8% lycra spandex

CUT: Boxer brief

PROS: Lightweight, Quick drying, Cheaper than merino

CONS: Less comfortable than merino

BEST FOR: Those looking for lightweight fast-drying synthetic


The ExOfficio Give-n-Go Boxer Briefs are extremely popular amongst both hikers and other outdoor enthusiasts. ExOfficio offer two options: a standard model and a “sport mesh” model. Our preference is for the latter. Both the standard model and the sport mesh model are made from nylon with a small percentage of lycra spandex. However, the sport mesh has a more lightweight and breathable weave.

There are some sacrifices in durability if you opt for the sport mesh model. The fabric tends to pill a bit, whereas this doesn’t seem to be the case with the standard model. However, this doesn’t really affect performance. Although more durable, we find that the standard model is heavyweight and slow drying compared to the sport mesh.

ExOfficio offers the boxer briefs in three different inseam lengths, each sold as a different product line. Our preference is for the 6-inch inseam, but shorter 3-inch and longer 9-inch inseams are also available. For comparison purposes, our top pick — the Smartwool Merino 150 Boxer Briefs — have a 4.75-inch inseam, and our runner-up — the Icebreaker Anatomica Boxer Briefs — have a 4.5-inch inseam.

If you aren’t keen to empty your wallet on merino, or you prefer the added durability of synthetic, then the ExOfficio Give-n-Go Sport Mesh Boxer Briefs are a good choice. Not only for hiking, but for any outdoor activities.

Runner-Up Synthetic: Arc’teryx Phase SL Boxers

MATERIALS: 100% polyester

CUT: Boxer brief

PROS: Lightweight, Quick drying, Snug fit

CONS: Expensive

BEST FOR: Those who want ultralight synthetic underwear

PRICE: $$$

Weighing in at just 2.3 oz (65 grams) the Arc’teryx Phase SL Boxers are a lightweight pair of undies. In fact they are the lightest of the bunch, although only by about 10 grams.

The material is also thinner, meaning that these are likely to be the most packable undies too.

If you want ultralight synthetic boxers then these are the ones for you.

A key upside of the Phase SL material is that it breathes & wicks well and is also quick to dry. This makes these boxers the perfect choice for active use. The material is stretchy and athletic. This helps to stop the boxers riding up during active use, but it also means these boxers are quite a tight (i.e. snug) fit. We think they find a good balance between support and comfort, but if you prefer your boxers feeling looser then perhaps look elsewhere.

Something to watch out for — aside from the price — is the fact that there is no front flap. Arc’teryx do not currently offer a model with a flap either, so if no front flap is a deal breaker for you then you will need to look elsewhere.

The Arc’teryx Phase SL Boxers are treated with an anti-microbial coating to improve odour resistance. This seems to work well, but is likely to fade over time after repeated washing. If you are looking for something for long multi-day trips or a thru-hike then merino wool might be a better option.

In terms of performance and comfort the ExOfficio Give-n-Go Sport Mesh Boxer Briefs and the Arc’teryx Phase SL Boxers are pretty much equal, but the ExOfficio offering wins on value.



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 on which baselayer material is best.

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 merino sheep… it produces the best next-to-skin layer for outdoor pursuits, including sitting round in a paddock.

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 boxer briefs 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.


Manufacturers usually market men’s hiking underwear as being either boxers or boxer briefs. Boxers are a looser cut, more closely resembling shorts. Boxer briefs provide a slightly more snug fit, particularly along the thigh. But cuts differ between manufacturers so these labels don’t always tell the full story.

Men’s underwear that is too form fitting and athletic don’t always work well on multi-day hiking adventures because with sweat and a lack of washing they can begin to chaff more than boxers slightly more relaxed fit. At the same time, boxers that are too loose can also rub and chaff. Rest assured that chaffing issues are pretty rare though.

Which type of cut is best for you really just depends on your preferences. We usually opt for a pair of boxers that are slightly snug but also have breathing room, like the Smartwool Merino 150 Boxer Briefs.


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, a seam or label at the centre-back of the waistband can sometimes be irritating if your backpack is rubbing on it.


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 don’t always 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.

Air drying on a washing line is always the safer option for merino wool, although the dryer on a low temp is also possible if you are in a real hurry.

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. But avoid direct sunlight if it is very hot and don’t hang garments if they are very wet — they might stretch! Although undies are usually ok.

Having said all that, here is our disclaimer:

“Always follow the manufacturers care instructions shown on the label” (sort of…).


If you loved this gear review article, then you'll likely love reading some of our other gear-fiend related articles:

Happy hiking, and take care out there in the wild!