6 Best Merino Wool Leggings for Thru-Hiking That Last an Entire Trail

You’re huddled in your tent as a cold front sweeps through the High Sierra, the temperature dropping faster than the sun. The difference between a shivering, restless night and a restorative sleep comes down to one critical piece of gear: your base layer bottoms. For a multi-month thru-hike, nothing handles the wild swings in temperature, moisture, and funk like merino wool leggings.

Disclosure: This site earns commissions from listed merchants at no cost to you. Thank you!

Why Merino Wool Dominates for Thru-Hiking

When you’re living out of a backpack for five months, your clothes need to do more than just keep you warm. Merino wool is the undisputed champion of long-distance trail apparel for one simple reason: it resists odor like nothing else. Unlike synthetic fabrics that can develop a permanent stink after a few days of sweat, merino’s natural antimicrobial properties mean you can wear these leggings for a week or more between washes without becoming a biohazard.

This isn’t just about being a considerate tent-mate; it’s about comfort and morale. Merino wool also has an incredible ability to regulate temperature. It will keep you warm even when it gets damp from tent condensation or a misty morning, and it breathes well enough to prevent you from overheating on a cool evening around camp.

The one historical knock against merino was durability. Early 100% merino garments could wear out quickly under the constant friction of a pack and trail life. Today, the best thru-hiking leggings solve this by blending merino with nylon or other synthetics, creating a "best of both worlds" fabric that offers merino’s comfort and odor-resistance with the toughness needed to survive an entire trail.

Smartwool Intraknit Thermal for Zoned Comfort

Imagine you’re pushing through the San Juan Mountains in Colorado, where a sunny afternoon can give way to a frigid, windy evening in minutes. You need a base layer that can vent heat where you’re sweating but insulate where you’re losing it. This is precisely where the Smartwool Intraknit shines, using 3D-knit, body-mapped zones to put ventilation and insulation exactly where your body needs them.

This isn’t just a simple tube of fabric; it’s an engineered piece of equipment. The seamless construction is a huge win for thru-hikers, as it drastically reduces the potential for chafing and hot spots over thousands of miles. The fit is athletic and articulated, moving with you whether you’re setting up your tent or stretching out after a long day.

The trade-off for this level of technical design is the price. It’s a premium option, but for hikers who prioritize cutting-edge performance and want to minimize friction points, the zoned comfort can be a game-changer for long-term trail life.

Icebreaker 200 Oasis: The Versatile Trail Staple

If you could only choose one pair of leggings for a trail like the Appalachian Trail, this would be a top contender. The Icebreaker 200 Oasis is the definition of a reliable, do-it-all base layer. Its 200g/m² fabric weight is the sweet spot for three-season versatility, providing enough warmth for chilly nights in the Smokies without being overkill for milder evenings in New England.

The Oasis isn’t built on flashy technology; it’s built on a proven track record. The 100% merino construction maximizes the wool’s natural benefits, offering incredible softness, breathability, and unmatched odor control. It’s the kind of gear you put on at camp and forget you’re even wearing.

Because it’s pure merino, it’s slightly more delicate than the nylon-core blends, so you wouldn’t want to bushwhack in them. But as a dedicated camp and sleep layer, its straightforward, effective design has made it a favorite of thru-hikers for years. It just works.

Patagonia Capilene Air for Ultralight Warmth

For the ultralight hiker counting every single gram, the Patagonia Capilene Air is in a class of its own. When you pull them out of the box, you’ll be shocked by how light they feel. The magic is in the airy, 3D-knit structure that traps a massive amount of warm air, providing a warmth-to-weight ratio that is simply off the charts.

This performance comes from an innovative blend of merino wool and recycled polyester, which helps the fabric dry faster and hold its shape better than pure wool. They are incredibly comfortable for sleeping, feeling more like a soft cloud than a piece of technical apparel. They pack down to almost nothing, disappearing in your pack until you need them.

However, this is a specialized piece of gear. The open, lofty knit that makes it so warm and light is also its biggest weakness. It’s highly susceptible to snags and abrasion, making it completely unsuitable for use as an outer layer. Think of it strictly as a high-performance sleeping garment or a mid-layer for very cold, low-activity moments.

Ridge Merino Aspect for Durability and Value

You’re planning a Continental Divide Trail thru-hike, where the terrain is rugged, the conditions are harsh, and your gear needs to be tough as nails. The Ridge Merino Aspect leggings are built for exactly this kind of abuse. Their secret weapon is a nylon-core spun fabric, where soft merino wool is wrapped around a strong nylon filament.

This construction gives you the on-skin comfort and performance of merino with the hidden strength and durability of nylon. These leggings can handle the abrasion of dirt, pack straps, and repeated washing cycles far better than most other merino options. They are true workhorses designed to last an entire 2,000+ mile journey.

Best of all, Ridge Merino delivers this durability and performance at a price point that is often more accessible than its main competitors. For the hiker looking for the absolute best blend of toughness, comfort, and value, the Aspect is incredibly hard to beat.

Minus33 Chocorua: A Workhorse for Cold Hikes

Starting the Pacific Crest Trail in a snowy March or tackling the last few hundred miles of the AT in a frosty October requires a different level of warmth. The Minus33 Chocorua is a midweight powerhouse built for cold weather. At 230 g/m², this legging provides serious insulation for nights when the temperature plummets below freezing.

Made from 100% merino wool, it prioritizes warmth and comfort. The fabric feels substantial and cozy, making it a welcome relief after a long, cold day on trail. It’s the kind of base layer that gives you the confidence to push into the shoulder seasons, knowing you have a reliable warm layer waiting in your pack.

This is not the legging for a summer hike; it would be far too warm. It’s also heavier and will take longer to dry than lighter-weight blends. But for hikers who run cold or are planning a trip where sustained cold is a real possibility, the Chocorua is a dependable and toasty sanctuary.

Ibex Woolies 2 for Supreme Next-to-Skin Feel

After a 25-mile day, the simple act of changing into your camp clothes can feel like the peak of luxury. The Ibex Woolies 2 are designed for that exact moment. Ibex is renowned for sourcing exceptionally high-quality, soft merino wool, and the next-to-skin feel of these leggings is second to none.

The Woolies 2 are a 240 g/m² midweight, making them a great option for three-season warmth with a focus on pure comfort. The construction is simple and clean, with flatlock seams and a comfortable waistband that won’t dig in while you sleep. They are the sleep pajamas you wish you could wear every single night.

Like other 100% merino pieces, they trade a bit of abrasion resistance for that supreme softness. They are best reserved for in-tent and sleeping bag use, where their comfort can be fully appreciated. For the thru-hiker who sees quality sleep as the most important tool for recovery, the Ibex Woolies are a worthy investment.

Choosing Your Merino Weight and Legging Fit

Navigating the world of merino wool can feel complex, but it boils down to two key choices: fabric weight and fit. The weight, measured in grams per square meter (g/m²), is the most important indicator of warmth.

• Ultralight (under 150 g/m²): Primarily for sleeping in hot weather or as a barely-there liner. Not common for thru-hiking leggings.
• Lightweight (180-200 g/m²): The thru-hiking sweet spot. This is the most versatile weight, offering solid warmth for its weight and working well across three seasons. The Icebreaker 200 Oasis is a perfect example.
• Midweight (230-260+ g/m²): For cold-weather hiking or for people who sleep cold. These provide significant warmth and are ideal for shoulder season or high-altitude treks. The Minus33 Chocorua and Ibex Woolies 2 fit here.

For fit, you want your leggings to be snug but not restrictive. A close-to-skin fit is essential for the fabric to do its job of wicking moisture away from your body and efficiently trapping body heat. Avoid a baggy fit, as loose fabric doesn’t insulate or manage moisture nearly as well. Ultimately, your leggings are part of a sleep system, not a fashion statement.

Don’t get paralyzed by the options. Any of the leggings on this list are fantastic choices that will serve you well from Springer Mountain to Katahdin. The "best" pair is the one that matches your budget, your hiking season, and your personal comfort priorities. Now, make a choice, pack your bag, and go have an adventure.