When it comes to warmth, comfort, and performance, merino wool underwear stands in a class of its own. A backpacking and true cold-weather essential, this natural fiber wicks away moisture, regulates temperature, and keeps you dry and odor-free all day. It’s the ideal foundation layer for skiing, hiking, or simply staying comfortable during everyday wear. Pairing perfectly with a merino wool base layer, this breathable underwear ensures you stay cozy without overheating. Additionally, merino wool clothing is a travel staple as it is quick-drying and wrinkle-resistant, and ideal for the needs of a one-bag backpacking lifestyle.
Traditionally, wool is perceived as an itchy, hot fiber, often used for sweaters or coats. Only recently has technology improved the ability to sort wool more effectively. This makes the wool fabric softer, less scratchy, and now machine washable. Unlike synthetic fabrics that trap sweat and odor, merino wool fibers work with your body’s natural temperature regulation.
It’s worth noting that merino wool underwear tends to be more expensive than typical cotton or synthetic pairs. That higher cost reflects the quality of the fiber itself, which is naturally antibacterial. As merino stays fresh longer, dries quickly, and doesn’t lose its shape, most people find they can own fewer pairs while still getting more wear out of them, making it excellent for travelers and hikers. Over time, the investment balances out through many wears.
In this guide, you will find boxers and briefs and thermal leggings, to soft, breathable women’s merino wool undies, each of which is carefully chosen to contain the highest merino wool percentage. We have selected underwear with over 85% merino wool. Also, like merino wool socks, some synthetic material may be required in underwear for stretch and shape.
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Save up to 44% on Black Friday Merino Wool Underwear and Base Layer Deals in 2025
Black Friday savings have officially kicked off, and we’re already tracking the best discounts on 100% merino wool underwear. Friday, November 28, 2025, deals have dropped early, with strong offers on trusted outdoor brands.
Here are the best Black Friday 100% merino wool base layers we’ve found so far:
20% off: MERIWOOL Men’s Merino Wool Boxer Briefs — Was $30.00, Now $24.00
23% off: Icebreaker Merino Anatomica Brief — Was $25.93, Now $20.00
9% off: Woolly Women’s Merino Hipster Brief — Was $34.00, Now $31.00
44% off: Merino.tech Merino Wool Hiking Socks (Crew) — Was $42.99, Now $23.99
38% off: Merino.tech 100% Merino Wool Base Layer Women Set – Was $142.99, Now $87.99
38% off: Merino.tech 100% Merino Wool Base Layer Mens Set – Was $129.99, Now $79.99
29% off: Kids Unisex 100% Merino Wool Base Layer – Was $48.00, Now $34.00
At a Glance
- Best Overall 100% Merino Boxer Shorts – Men’s Merino Boxers By Woolly
- Best 100% Merino Boxer Briefs – Men’s 5″ Merino Boxers Briefs By Woolly
- Best Boxer Brief with Fly Options – Icebreakers Merino Protect Merino Wool Underwear Men
- Best 100% Merino Boxer Brief Set – Merino.tech Merino Wool Underwear Mens
- Best 100% Merino Boxer Briefs – MERIWOOL Mens Boxer Briefs Merino Wool Underwear
- Best Briefs – Icebreaker Mens Merino 150 Anatomica Briefs
- Best Merino Wool Leggings – Icebreaker Merino Mens Standard 175 Everyday Legging
- Best Overall 100% Merino Women’s Underwear– Women’s Merino Wool Bikini By Woolly
- Best Women’s Fitted Boxer 100% Merino Shorts – Women’s Merino Boxer Short By Woolly
- Best Women’s 100% Merino Hipster – Women’s Merino Hipster Brief By Woolly
- Best Women’s 100% Merino Bikini Fit – Women’s Merino Wool Bikini By Woolly
Merino Wool Underwear
Woolly’s men’s boxers deliver everything you want from merino wool: softness, odor resistance, and breathability. Made from 100% ultralight Australian merino wool, these boxers are designed for long-lasting comfort and high performance whether you’re hiking, working, or relaxing. The tagless, flatlock-seam construction eliminates irritation, while the natural fibers wick away sweat and regulate your temperature all day long.
Key specs
Fabric 100 percent ultralight Australian merino wool
Care hand wash only
Fit tagless with flatlock seams
Features moisture wicking, odor resistant, temperature regulating
These 5″ Merino boxer briefs from Woolly provide the perfect mid-length coverage for added comfort during high-movement activities. The superfine Merino wool fabric keeps you cool, dry, and odor-free, while maintaining a soft, second-skin feel. Ideal for hiking, running, or layering under outdoor gear, they deliver premium performance with a minimalist design.
Key specs
Fabric 100% Merino wool 150gsm
Length 5-inch inseam
Features Flatlock stitching, tag-free, moisture-wicking
Designed for extended coverage and comfort, the Icebreaker Anatomica Long Boxers use 150-weight Merino wool for lightweight warmth and softness. They offer natural stretch and excellent breathability, reducing chafing during long hikes or cold-weather activity. The longer inseam adds security under layers while maintaining the flexibility you’d expect from premium Merino.
Key specs
Fabric 83% Merino wool, 12% nylon, 5% elastane
Weight 150gsm
Features Odor-resistant, temperature-regulating, flatlock seams
Smartwool’s boxer briefs offer that classic balance of durability and comfort. Made from soft merino wool with added nylon for structure, they’re perfect for daily wear or light outdoor activity. Their moisture-wicking and anti-odor qualities make them a practical, all-season essential for men who appreciate natural fibers that last.
Key specs
Fabric 88 percent merino wool, 12 percent nylon
Care hand wash only
Fit standard
Features moisture wicking, breathable, odor resistant
Smartwool’s Merino Boxer Briefs combine vibrant design with high-performance fabric. The ultra-soft Merino wool blend keeps you dry and comfortable throughout the day, while the contoured pouch and flat seams prevent irritation. With a range of color options, they bring personality and practicality to your base layers.
Key specs
Fabric 88% Merino wool, 12% nylon
Features Wide elastic waistband, anti-chafe seams
Fit Regular
Best for Everyday wear and athletic comfort
For a traditional boxer fit made from natural fibers, these Smartwool Merino Boxers deliver timeless comfort. Lightweight, breathable, and quick-drying, they’re perfect for relaxed days or layering under hiking pants. Their classic cut and high-quality Merino fabric offer a naturally cool and odor-free experience.
Key specs
Fabric 88% Merino wool, 12% nylon
Fit Loose, relaxed cut
Features Breathable, odor-resistant, moisture-wicking
Best for Lounging, travel, and warm climates
These 100% superfine merino wool boxers deliver total comfort and temperature control. Designed for year-round wear, they’re soft, lightweight, and naturally breathable. Whether under ski gear or casual clothes, they keep you dry, fresh, and itch-free all day.
Key specs
Fabric 100 percent superfine merino wool
Care delicate cycle or hand wash
Fit snug and supportive
Features breathable, moisture wicking, odor resistant
Crafted from ultrafine 17.5-micron merino wool, these boxer briefs are luxuriously soft and regulate temperature in all conditions. They dry quickly, resist odor, and provide a gentle stretch for active movement. Perfect for layering or solo wear, they’re a top performer for comfort and breathability.
Key specs
Fabric 100 percent merino wool, 180 g/m² weight
Care machine wash cold
Fit fitted
Features quick drying, moisture wicking, odor resistant
Lightweight and supportive, the Icebreaker Anatomica Briefs provide full freedom of movement without bulk. The Merino fabric naturally resists odor and regulates temperature, making them ideal for high-output days or multi-day treks. They offer a sleek, body-hugging fit that feels barely there.
Key specs
Fabric 83% Merino wool, 12% nylon, 5% elastane
Weight 150gsm
Features Flatlock seams, breathable, odor control
Best for Running, travel, and layering
Built for everyday comfort and layering, these leggings combine warmth and softness for year-round use. Naturally breathable and odor resistant, they adapt to your body temperature to keep you warm without overheating. A reliable essential for travel, hiking, or lounging.
Key specs
Fabric 100 percent merino wool
Care machine wash cold, dry flat
Fit contoured
Features thermal regulating, odor resistant, moisture wicking
Best Women’s Merino Wool Underwear
This Woolly bikini combines everyday comfort with technical performance. Made from 100% merino wool, it regulates temperature naturally, wicks moisture efficiently, and provides exceptional softness against the skin. The low-rise design, flat seams, and smooth waistband make it invisible under clothing, while the breathable fibers help maintain freshness all day.
Key specs
Fabric 100% Merino wool
Fit Low-rise bikini cut
Features Moisture-wicking, breathable, odor-resistant
Designed for active comfort and extra coverage, these fitted boxer shorts from Woolly are perfect for hiking, lounging, or sleeping. The fine merino fibers allow free airflow and wick away sweat, keeping you dry and comfortable in all conditions. With a close fit and soft elastic waistband, they stay put without restriction, even during movement.
Key specs
Fabric 100% Merino wool
Fit Mid-length fitted boxer
Features Flat seams, odor-resistant, temperature-regulating
The Woolly Hipster Brief is a sporty, low-profile style designed for performance and comfort. The merino wool construction provides a soft, breathable feel that adapts to your body temperature. It’s ideal for layering under leggings or activewear, staying comfortable whether you’re working out or relaxing.
Key specs
Fabric 100% Merino wool
Fit Mid-rise hipster style
Features Breathable, lightweight, moisture-regulating
A flattering, feminine cut that feels weightless and soft, the Woolly Merino Bikini is an everyday staple. It’s naturally odor-resistant and moisture-wicking, ensuring all-day freshness without irritation. This piece transitions easily from trail to town, maintaining shape and comfort even after repeated wear.
Key specs
Fabric 100% Merino wool
Fit Classic bikini
Features Seamless feel, quick-drying, anti-odor
For a sleek, no-show fit, the Icebreaker Siren Thong combines luxury and function. Made from ultrafine merino wool, it’s soft, stretchy, and naturally breathable. The minimal design makes it perfect under leggings or fitted clothing, with flatlock seams to prevent rubbing during activity.
Key specs
Fabric 83% Merino wool, 12% nylon, 5% elastane
Fit Low-rise thong
Features Lightweight, odor-resistant, flexible stretch
Blending the comfort of a bikini with slightly more coverage, the Icebreaker Siren Hipkini offers softness, breathability, and freedom of movement. It’s made from lightweight merino wool with just enough stretch for a smooth fit, perfect for travel, hiking, or everyday wear.
Key specs
Fabric 83% Merino wool, 12% nylon, 5% elastane
Fit Mid-rise hipkini
Features Soft waistband, breathable, temperature-regulating
Why Choose Merino Wool Underwear?
Merino wool underwear is lightweight, breathable, excellent for travel, and acts as a high-performance base layer that adapts to your lifestyle. Its natural fibers regulate body temperature, wick moisture, and resist odor far better than synthetic materials. Also as it is lightweight and breathable, it’s perfect for everything from backcountry adventures to backpacking.
Merino Wool vs Synthetic Underwear
While synthetics dry quickly, they often trap odor and lose softness over time. Merino wool, on the other hand, stays fresh longer thanks to its natural antibacterial properties. It’s also temperature-regulating, meaning you can wear it in both warm and cold conditions without overheating or feeling clammy.
Caring for Merino Wool Underwear
To keep your merino wool garments soft and long-lasting, wash them on a gentle cycle or by hand in cool water. Also avoid bleach and fabric softeners, which can damage the fibers. Always air dry or line dry flat to maintain shape and elasticity.
The Best Way to Layer Merino Wool
For full-body comfort and performance, pair merino wool underwear with a base layer and top it with a mid-weight fleece or insulated shell. This natural layering system provides maximum warmth, breathability, and odor control during cold-weather adventures.
FAQs
Is merino wool underwear itchy?
No. Modern merino fibers are incredibly fine, creating a soft, smooth texture that feels gentle against the skin.
Can I wear merino wool underwear in warm weather?
Yes. Merino wool also naturally regulates temperature, keeping you cool in summer and warm in winter.
How often should I wash merino wool underwear?
Thanks to its odor-resistant properties, you can wear merino underwear multiple times before washing. Just air it out between uses.
Is merino wool sustainable?
Yes. Merino wool is also biodegradable and renewable, making it an eco-friendly alternative to synthetics.
What’s the difference between 100% merino and blends?
Pure merino offers the softest and most natural feel, while blends add durability and stretch for active use.
Enjoyed our guide? Read more
Best Merino Wool Sweater for Men, Women and Kids
The Ultimate Women’s Base Layer Merino Wool Guide
The Best 100% Merino Wool Base Layer for Men
