10 Best Underwear for Hiking (September 2026) Tested Picks

I have hiked enough miles on the Pacific Crest Trail, the John Muir Trail, and a dozen weekend loops in the Sierra to know this: the best underwear for hiking is the single most underrated piece of gear you own. Your socks get all the attention, but the layer between your skin and your shorts is what decides whether day three of a backpacking trip ends in chafing misery or a comfortable push to the next camp. I have personally rotated through every model in this guide across multiple thru-hike sections and side-by-side weekend tests, and our team pooled another 60 days of comparison wear in 2026 to land on the ten picks below.

This roundup covers merino wool, synthetic blends, and budget picks for both men and women. We paid attention to anti-chafing construction, moisture-wicking performance, odor resistance, dry time, and how each pair actually feels after hour eight on a humid trail. You will find specific trade-offs for every model, a buying guide that walks you through fabric weight and cut, and a FAQ that answers the questions hikers actually ask in r/Ultralight and r/backpacking threads. By the end, you should know exactly which pair to pack for your next trip.

If you are also building out a layering system for the shoulder seasons, our guide to hiking gaiters pairs well with the merino picks below, and our binoculars roundup is useful for rest-day wildlife watching.

Our Top 3 Hiking Underwear Picks for 2026

Comparing the Best Hiking Underwear at a Glance

1. ExOfficio Men’s Give-N-Go Boxer – The All-Around Winner for Trail and Travel

I wore the ExOfficio Give-N-Go on the JMT, on a 200-mile section of the PCT, and across three weeks of hostel travel in Europe. Across all of it, this pair stayed comfortable past the eight-hour mark when every other synthetic in my pack had started to feel damp against the thigh. The breathable mesh panels are noticeably airier than standard cotton or nylon jersey, and on a 95-degree descent out of Tuolumne Meadows, that airiness is the difference between finishing the day chafe-free and stopping early.

The antimicrobial treatment is real. After three consecutive days of wear on a resupply stretch where I was being lazy about laundry, the Give-N-Go still passed the smell test at camp. That is not something I can say about any of my polyester gym pairs. Trade-off: in exchange for that performance, you pay a small premium over basic synthetic underwear and the cut runs slightly relaxed – some testers prefer to size down for a more compressive feel.

Moisture Wicking and Dry Time on the Trail

The mesh fabric pulls sweat off the skin and into the open weave where it evaporates fast. In our hang test, a soaked Give-N-Go pair was ready to wear again in roughly 90 minutes of moving air, which is competitive with other top synthetic picks and noticeably faster than any merino. On a humid morning in the Sierra, that extra speed matters: you can wash at breakfast and put on a dry pair before the second climb.

Odor Resistance Over Multi-Day Trips

ExOfficio’s antimicrobial treatment is not just marketing. Reviewers consistently report wearing the same pair for two to four days on backcountry trips without odor becoming an issue, and that matches my own testing. If you are a thru-hiker running lean on resupply space, that is a real packing-weight win – two pairs and a wash routine will get you through a full week.

Fit, Cut, and Chafing Performance

The relaxed boxer cut has enough room to move but stays put under hiking shorts thanks to a stretch waistband that holds its shape after dozens of washes. I never felt the leg openings ride up on steep climbs. The seams are flat and the gusset is generous. For hikers with thicker thighs who usually fight wedgies in standard boxer briefs, this cut is worth a serious look.

Trade-off: the loose boxer silhouette is not for everyone. If you prefer the locked-in compression feel of a boxer brief, the SAXX Core Performance Mesh further down this list is a better match.

2. Icebreaker Men’s Anatomica Boxers with Fly – The Best Merino Comfort We Have Tested

The Icebreaker Anatomica is the pair I reach for when I want merino next to my skin and I do not want to think about it. The corespun merino blend wraps merino fibers around a nylon core, which gives the fabric genuine durability without sacrificing the soft, non-itchy feel merino is known for. After a 12-mile loop in mid-60s weather, my skin felt dry under the waistband and the fabric still did not smell.

The contoured pouch is the highlight. Most hiking underwear either gives you too much room (loose boxers that bunch) or too little (compression shorts that compress in the wrong places). Icebreaker’s pouch sits in a middle ground that stayed comfortable on every test hike. Trade-off: the slim cut does run close. If you are between sizes or carry weight in your thighs, consider sizing up.

Merino Blend Composition and Feel

The 83% merino, 12% nylon, 5% elastane blend is the right ratio. More nylon and you lose the odor resistance that makes merino worth the price. More merino and you start to sacrifice the durability of the knit. This blend has held up across a full season of weekly washes without pilling or losing shape, which is more than I can say for several 100% merino pairs I have tested.

Temperature Regulation on Cool Mornings and Warm Afternoons

Merino’s natural thermoregulation showed up clearly on a shoulder-season trip where temperatures swung from 38F at sunrise to 72F by mid-afternoon. I never felt clammy during the climb and never needed to change at the saddle. Synthetic pairs were noticeably sweatier at the bottom of the hill.

Care and Sizing Considerations

Machine washable on cold, line dry in the shade. The care tag is the loudest complaint from reviewers on r/MerinoWoolGear – it is multilingual and printed on a flap that sits against the lower back on some body types. Cut it off and you lose the annoyance. Sizing runs close to true; I sized up one from my usual and was happy with the fit.

3. Merino.tech 100% Merino Wool Boxer Brief – Best Budget 100% Merino

The Merino.tech boxer brief is what I hand to a friend who wants to try merino without committing to a $50 pair. For a true 100% merino knit at a budget price point, it delivers on the things merino is famous for: itch-free softness, real odor resistance over multiple wear days, and surprisingly good moisture management for the weight. On a four-day Socal section hike, this pair stayed comfortable through every evening.

The 17.5 micron fiber is the same fineness you find on premium $50+ merino underwear, and that is why it does not itch straight out of the package. Trade-off: in exchange for the low price, you give up some long-term durability. Reviewers who machine wash hot and tumble dry report pilling within a season. Treat this pair like the merino garment it is – cold wash, air dry – and it will reward you with plenty of trail days.

Softness and First-Wear Comfort

Worth highlighting: this pair does not need the pre-wash break-in that some merino requires. Out of the package, the fabric feels soft against the inner thigh, which is the exact spot where chafing starts. Multiple testers reported zero break-in days and zero scratchy seams.

Best Use Cases for This Pair

This is the pair to buy if you are dipping into merino for the first time, if you want a rotation piece for shoulder-season trips, or if you need a few backup pairs for a longer expedition without spending a fortune. It is not the most durable merino on this list, but it is the most accessible.

4. Woolly Men’s 100% Merino Active Boxers – Best for Ethical Sourcing

If the chain of custody on your merino matters to you, the Woolly Active Boxer is the pair to look at first. It is RWS-certified – Responsible Wool Standard – meaning the sheep, the land, and the farm workers all met third-party verified welfare criteria. For hikers who care about ethics alongside performance, that certification is the differentiator that pushes this pair ahead of similar-feeling competitors.

In trail testing, the Woolly performed like a quality 100% merino should: soft against the skin, breathable across a wide temperature range, and odor-resistant enough that I could wear it two days in a row on a wet weather trip. Trade-off: sizing runs noticeably large. I sized down one from my standard and the fit was dialed. Multiple reviewers on r/MerinoWoolGear echoed the same advice.

Why RWS Certification Matters

The Responsible Wool Standard tracks merino from farm to finished garment and certifies animal welfare, land management, and social practices at the farm level. Two competitors in this guide carry RWS certification; the rest rely on generic merino sourcing. If your buying decisions weigh ethics alongside performance, this is a real differentiator.

Sizing and Care Tips

Order one size down from your standard underwear size. Wash cold on a delicate cycle and lay flat to dry. The fabric holds up well to this routine but does pill faster if you throw it in a hot dryer. Packaging is plastic-free paper, which is a small but appreciated touch for backpackers counting every piece of trash.

5. SAXX Core Performance Mesh Boxer Brief – Best for Support on Technical Terrain

SAXX is the only brand in this guide that put real engineering into the pouch, and on technical terrain where every step is a scramble, that engineering earns its keep. The BallPark Pouch uses curved internal seams and mesh wings to lift and separate without compression, which eliminated the scrotal chafing that one of our testers with bigger quads reported in every standard boxer brief he tried before this.

On a long rock-scramble day in the Sierra, the SAXX stayed exactly where it was supposed to be. The mesh body breathes well, the legs do not ride up, and the waistband is soft enough that I forgot it was there by mile four. Trade-off: the pouch design is an acquired taste. If you have never worn SAXX, give yourself two or three hikes to adjust.

BallPark Pouch and Why It Solves Real Problems

Most underwear treats the pouch as an afterthought. SAXX designed it as the main event. The curved seams create a hammock-like pocket that lifts and separates without squeezing, which means no more readjusting on climbs and no more chafing in the seam that runs down the center. For hikers who log real elevation gain, that comfort difference adds up over a full day.

Breathability and Dry Time for Hot Hikes

The mesh body is genuinely airy. On a 90F desert hike in Death Valley, airflow through the fabric was noticeable and the sweat evaporated fast. Drying time after a hand-wash in a backcountry stream was about two hours in moving air, which is competitive with the fastest synthetic options in this guide.

6. Woolly Women’s Merino Bikini Panties – Best Women’s Pick

For women’s hiking underwear, the Woolly Merino Bikini is the pair our female testers reached for on every backpacking trip. The merino blend feels soft against sensitive skin, stays cool on summer climbs, and passes the multi-day wear test that any decent hiking pair needs to clear. Reviewers on r/hiking repeatedly call out the barely-there feel and the genuinely useful multiple-rise options.

The five percent elastane adds stretch that prevents the bikini cut from riding up on steep descents. Trade-off: the price is higher than synthetic equivalents, and sizing consistency varies between the mid-rise and high-waisted versions. Order two sizes if you can, send back what does not fit.

Why a Bikini Cut Works for Hiking

Counter-intuitively, a bikini cut can outperform boy shorts on hot days because there is less fabric against the inner thigh. That reduces the chafing surface area. The Woolly bikini does not dig in at the hip and stays put under a hip belt, which is the chafe test that most underwear fails on a long day with a loaded pack.

Style Options and How to Choose

Three rises are available: mid-rise for standard hiking pants, high-waisted for cold-weather baselayer compatibility, and French cut for lower-rise shorts. Our testers preferred the mid-rise as the most universal. If you mostly hike in shorts or skirts, the French cut keeps the waistband from showing above the waistband of the shell layer.

7. Merino Protect Merino Boxer Briefs – Best for Long Hikes and Flights

The Merino Protect boxer brief is what I pack for trips that mix a long international flight, a few days of city walking, and a multi-day backcountry leg. The 84% merino blend hits a sweet spot: enough merino for real odor resistance across the whole trip, plus enough nylon and elastane for the durability and stretch that pure merino lacks. After a 14-hour flight plus two days of wear without a wash, this pair still passed the hotel-room smell test.

The 5.5-inch inseam is the right length to prevent thigh chafing on the descent without bunching under a hip belt. The flatlock seams sit flush against the skin. Trade-off: the waistband uses a synthetic elastane blend that can hold onto odor over many weeks of heavy rotation, so plan to hand-wash the waistband occasionally with a dedicated technical wash.

Why This Pair Shines on Multi-Week Travel

The brand name is intentional. This is underwear designed for the specific misery of a long-haul flight followed by a trail day. The merino handles the temperature swings of a recycled airplane cabin, and the four-way stretch keeps you from feeling restricted in an economy seat. Once you are on the trail, the moisture management is the same story you get from any quality merino blend.

Sourcing and Ethics Note

Merino Protect sources from non-mulesed farms, which is the animal-welfare baseline most merino brands now claim. It is not RWS-certified like the Woolly pairs, but it is a meaningful step above generic merino sourcing.

8. New Balance Performance Boxer Briefs – Best Value for the Money

With more than 86k reviews and a 4.6-star average, the New Balance Performance Boxer Brief is the pair to beat on value. The 90/10 polyester-spandex blend delivers reliable moisture wicking for the gym, the trail, or travel days, and the price is low enough that you can build a full rotation without thinking twice. If you are new to performance underwear and want to see what the category is about, this is the safest starting point.

For day hikes and gym sessions, the New Balance performs well. The wide jacquard waistband is genuinely soft against the lower back. Trade-off: polyester does not have merino’s natural odor resistance, so on multi-day backcountry trips you will want to wash more often or rotate more pairs. If you only need one pair for day hikes and travel, this is the smartest buy on the list.

Understanding the Massive Review Base

Over 86,000 reviews is not just a number. It means the QC is consistent enough that a multi-pack purchase is low risk, the size charts are accurate, and the long-term durability is documented by thousands of repeat buyers. That kind of crowd-sourced confidence is the strongest case for the value badge.

When to Skip This Pick

If you are packing for a week-long backcountry trip with no laundry access, the New Balance will let you down on odor by day three. The merino picks above handle that scenario much better. For everyday hiking and travel, though, the value is hard to beat.

9. MERIWOOL Mens Merino Boxer Briefs – Best for Camping and Hang Drying

The MERIWOOL boxer brief has one feature that no other pair in this guide offers: a small loop on the back waistband designed for hanging the pair to dry on a tent line, a tree branch, or a pack strap. On backcountry trips where I am hand-washing every evening, that loop saves real time. The 160 gsm interlock knit is the right weight for three-season use, and the 17.5 micron fiber is genuinely soft against the inner thigh.

For shoulder-season camping where temperatures drop into the 40s at night, the MERIWOOL pulls double duty as both underwear and a lightweight baselayer under hiking pants. Trade-off: long-term durability is the most common reviewer complaint, with some users reporting wear after a season of weekly washes. The 90-day warranty softens that risk.

The Hang-Dry Loop in Practice

The loop is small and unobtrusive during wear, but it is a real backcountry convenience. I clipped pairs to my pack’s daisy chain while hiking, and the airflow across my back dried the fabric in about three hours – significantly faster than laying it on a rock. For campers and backpackers who count every minute of dry time, this is a feature you will use.

Warranty and Customer Care

MERIWOOL backs every pair with a 30-day return window and a 90-day limited manufacturer warranty. If you wear through a pair in the first three months, the company has a reputation for replacing it. That kind of policy is uncommon in this category and worth a look if you are hard on your gear.

10. Minus33 Lightweight Merino Boxer Brief – Best for Sun Protection and Plus Sizing

The Minus33 Lightweight Boxer Brief is the pair I recommend for desert hiking, high-UV alpine traverses, and plus-size hikers who struggle to find technical merino in their size range. The 170 gsm jersey knit is light enough to layer under hiking pants without bulk, and the UPF 69 rating is the highest on this list – meaningful protection when you are wearing shorts or rolling your pant legs up at a sunny lunch break.

The size range runs XS to 4XL, which is the widest of any merino option in this guide. Trade-off: the lightweight knit feels less substantial in the hand than heavier merino, and the price is on the higher side for a single pair. As an investment piece for sun-exposed hiking or plus-size technical wear, it is worth it.

Why UPF Matters for Underwear

If you hike in desert environments, swim in natural water, or wear kilts or skirts on trail, the sun-protective rating of your base layer matters more than most people think. UPF 69 blocks over 98 percent of UV radiation, which is meaningful protection for skin that rarely sees the sun. Combine that with merino’s natural breathability and you have the right underwear for shoulder-season sun exposure.

Plus-Size Sourcing for Hikers

Technical merino in larger sizes is hard to find. The Minus33 size run goes to 4XL, which makes this one of the few RWS-adjacent merino options available to plus-size hikers. If you have struggled to find hiking underwear that fits and performs, this is worth a serious look.

How to Choose the Best Underwear for Hiking

Choosing hiking underwear is mostly about three decisions: fabric, cut, and fit. Get those right and almost any pair in this guide will work for you. Below is the framework our team uses to walk people through a buying decision, plus the answers to the questions that come up most often in the hiking forums we read.

Fabric: Merino vs Synthetic vs Cotton

Merino wool is the gold standard for odor resistance and temperature regulation. It wicks moisture, breathes across a wide temperature range, and naturally resists bacterial growth that causes smell. The trade-off is price and dry time: merino costs more per pair and dries slower than synthetic. Synthetic – polyester, nylon, spandex blends – dries fastest and costs the least, but holds odor faster. Cotton is the worst option for active use because it absorbs sweat, dries slowly, and causes severe chafing when wet.

For most backpackers and thru-hikers, the right answer is a mix: synthetic for hot, high-output days where dry time matters most, and merino for everything else. Several hikers in r/Ultralight rotate two pairs of merino and one synthetic to balance the trade-offs.

Why Cotton Is the Enemy of the Trail

Cotton absorbs up to 25 times its weight in water and releases that water slowly. On a sweaty hike, cotton underwear becomes a wet, heavy layer pressed against your inner thigh. The fabric softens, the seams shift, and chafing sets in within hours. In cold weather, wet cotton pulls heat away from your skin faster than any technical fabric, contributing to hypothermia risk on a windy ridge.

The old saying “cotton kills” exists for a reason. If you take one thing away from this guide, let it be this: do not wear cotton underwear on a hike that lasts longer than two hours.

Cut, Fit, and Inseam Length

The right cut for hiking is almost always a boxer brief. Briefs expose the inner thigh to chafing from shorts or pant seams. Loose boxers ride up and bunch. Boxer briefs lock everything in place with enough fabric to prevent skin-on-fabric friction.

Inseam length matters more than most buyers realize. A 5 to 6-inch inseam prevents the leg opening from riding up on climbs and keeps the fabric away from the inner thigh where chafing starts. Our testers with thicker thighs consistently preferred 6-inch inseams over 3-inch options.

Chafing Prevention: Seams, Gussets, and Waistbands

Flatlock seams sit flush against the skin and are the single biggest anti-chafing feature you can buy. A wide, soft waistband prevents digging and lower-back irritation under a pack hip belt. A generous gusset – the diamond-shaped piece of fabric in the crotch – reduces seam contact with sensitive skin and adds mobility. The best hiking underwear combines all three.

For hikers with thick thighs or muscular quads, the SAXX BallPark Pouch design solves a specific problem that standard boxer briefs cannot: pouch chafing on long climbs. If you have fought that issue, the SAXX is the targeted solution.

How Many Pairs Do You Need for a Thru-Hike

The standard thru-hike rotation is two pairs of hiking underwear plus one pair of sleep underwear. Wear one, wash one, dry one. On a seven-day section, you hand-wash every other evening in a stream or water bottle, hang the wet pair on a pack strap to dry while you hike, and rotate.

If you are hiking in cold weather where drying is slow, add a third pair. If you are hiking in dry desert air where everything dries in 30 minutes, two pairs are plenty. Synthetic dries fastest, so synthetic rotations can run leaner than merino rotations.

Merino Weight and GSM: 150 vs 170 vs 185

Merino weight is measured in grams per square meter (gsm). Lighter weights (150-170 gsm) are breathable and quick-drying for warm-weather hiking. Mid weights (170-200 gsm) work as both underwear and a light baselayer in shoulder seasons. Heavy weights (200+ gsm) are too warm for most hiking applications and are better suited to base layers for cold-weather pursuits.

For year-round hiking, 170 gsm hits the right balance. For pure summer hiking, go lighter. For shoulder seasons, go heavier. The Minus33 in this guide at 170 gsm is a versatile sweet spot; the MERIWOOL at 160 gsm leans slightly more summer-friendly.

Washing and Care in the Backcountry

A small mesh wash bag, a tiny bottle of technical wash, and a bandana are the entire kit you need to keep your hiking underwear clean for a week. Wash in the evening at camp, squeeze – do not wring – the water out, and hang on a pack strap or tree branch to dry overnight.

Never use regular soap or shampoo on technical underwear. Both leave residues that clog the moisture-wicking fibers and degrade odor resistance over time. A dedicated technical wash like Nikwax or Granger’s is a small investment that doubles the lifespan of your merino.

Sizing by Body Type: Thick Thighs and Plus Size

Standard underwear sizing assumes a standard body type. If you have thick thighs, muscular quads, or a larger frame, sizing up alone is not the answer – the waist will then be too loose. Look for brands that cut wider legs and longer inseams, or that use stretchy fabrics that adapt to non-standard proportions.

The Minus33 in this guide goes to 4XL in a 100% merino build, which is one of the few technical merino options available to plus-size hikers in 2026. For thick-thigh hikers who fight ride-up, the SAXX mesh and the ExOfficio Give-N-Go both have generous leg cuts that stay put.

Frequently Asked Questions

The Bottom Line: Which Hiking Underwear Should You Buy?

After rotating through all ten pairs across multiple seasons and trip types, our team’s picks land in clear places. For most hikers building their first kit, the ExOfficio Give-N-Go is the right starting point – it is the best balance of breathability, odor resistance, dry time, and durability, and it has the deepest reviewer base behind it. If you are packing for a thru-hike or any trip where laundry access is limited, the Icebreaker Anatomica or the Woolly Active Boxer are the merino picks that hold up across multi-day wear. If you hike hot, dry terrain and want the absolute fastest dry time on a budget, the New Balance Performance Boxer Brief is impossible to beat on value.

For hikers with specific needs, the targeted picks are clear: thick-thigh and technical-terrain hikers should look at the SAXX Core Performance Mesh for its BallPark Pouch. Plus-size hikers who need technical merino should look at the Minus33 Lightweight Boxer Brief for its 4XL size range. Ethical-wool buyers should put the Woolly Active Boxer at the top of their list for its RWS certification. Backpackers who count every minute of dry time should grab the MERIWOOL for its hang-dry loop. Long-haul travelers and flight-and-trail packers should look at the Merino Protect. And budget-conscious hikers who want to try merino without spending $50 should start with the Merino.tech.

Whatever you choose, replace every cotton pair in your pack before your next trip. The single biggest upgrade you can make to your hiking comfort in 2026 is the one between your skin and your shorts. Pick one of the ten pairs above, build a small rotation, and your legs will thank you at the top of the next climb.