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Base Layer Bottoms

Top Picks

How we choose: The best base layer bottoms highlighted here were selected based on 59 reviews of 50 products. Our top picks are those that are readily-available in the United States and have received the highest overall ratings from reviewers.

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Ibex Woolies Tech Bottoms

user rating: 5 of 5 (1 review)

Versatile lightweight merino blend layer, perfect for winter backcountry use, chilly nights in camp, and just lounging around at home on cold days.

Reasons to Buy

  • Soft
  • Good fit
  • Breathable
  • Warm, but not too warm
  • Stretchy
  • Reasonably quick drying
  • Easy to care for

Reasons to Avoid

  • It would be nice to have an option for a shorter inseam

I’ve been a huge fan of Ibex clothing for many years. The Ibex Indie hoody I bought probably twenty years ago, is still one of my favorites. I was sad when they announced that they were closing a number of years ago and have been pleased to see that they have returned. I was eager to give these bottoms a try. I received the Woolies Tech Bottoms in late spring when our Northern California weather was generally too warm to use them much initially, but with colder and wetter weather descending on us this winter, I’ve been wearing them a lot.  Campground fashion statement rearview Fit and Comfort: The fit of the Woolies Tech Bottoms is as would be expected.

Read more: Ibex Woolies Tech Bottoms review (1)

Patagonia Capilene Air Bottoms

user rating: 4.5 of 5 (1 review)

The Patagonia Capilene Air Bottoms are Patagonia’s newest base layer design which utilizes a unique seamless knit construction that is composed of 51 percent merino wool and 49 percent Capilene recycled polyester. This results in a very stretchy insulation layer that is both light and warm. The knit construction provides a nice thickness that works extremely well inside of waders for long days fishing in cold streams. Overall this is a great base layer, especially for colder conditions.

Reasons to Buy

  • Very warm
  • Not itchy for wool
  • Seamless design adds to comfort – very flat transitions
  • Doesn’t hold odors
  • Nice comfortable waistband
  • Responsibly sourced wool and recycled polyester

Reasons to Avoid

  • Lack of a fly opening
  • Might be too warm for many activities
  • Some shrinkage in the pant leg length
  • Pills pretty easily

Overview The Patagonia Capilene Air Bottoms are Patagonia’s newest base layer design that follows Patagonia’s long tradition of developing new fabrics with improved performance while also trying to find ways to minimize the impact on the environment. The Capilene Air Bottom fabric is a unique a 3-D seamless knit construction that utilize fibers made from 51 percent responsibly sourced merino wool and 49% Capilene recycled polyester.  The resulting bottoms are light, warm and very comfortable to wear.

Read more: Patagonia Capilene Air Bottoms review (1)

Outdoor Research Enigma Bottoms

user rating: 4.5 of 5 (1 review)

The Outdoor Research Enigma Bottom is a base layer whose forte is wicking moisture and keeping you dry when you’re active; though the fabric has some wool content, it’s mostly synthetic (12% merino, 88% polyester). The fabric is relatively thin and very stretchy and slightly prone to pilling in high-friction areas. It’s an outstanding option for high-output cool and cold weather activities (four-season if you live in a cooler place), except you’ll want to wear them under a shell or fleece when it’s really cold.

Reasons to Buy

  • Moisture handling
  • Comfort
  • Stretchy, great range of motion

Reasons to Avoid

  • Prone to pilling
  • Not as warm as layers that are heavier-weight or that have more wool

BASIC INFORMATION Outdoor Research's Enigma base layers are a combination of wool and polyester—12% merino and 88% Drirelease polyester. Check out my recent reviews of the Enigma Half Zip top and Boxer Briefs. The synthetic part is Outdoor Research's DriRelease E.C.O., "Environmentally Correct Origins,” which is made from 100 percent post-consumer recycled PET, the material used to make plastic bottles and containers, and blended with natural fibers like wool. The bottoms have a one-inch wide elastic waistband, a fly, and a couple of seams mid-leg that run roughly above and below the knee.  FIT AND FEEL The Enigma Bottoms are true to size—you can rely on Outdoor Research's size chart.

Read more: Outdoor Research Enigma Bottoms review (1)

Smartwool Classic All-Season Merino Base Layer Bottom

user rating: 4.5 of 5 (1 review)

A full-length base layer bottom that has real value on trail in all four seasons. Smartwool's Classic All-Season Merino Base Layer Bottom uses a 150g wool/nylon blend fabric that is heavy enough to add warmth when layered but light enough to use as a hiking tight in warm weather. Comfort and durability for use all year.

Reasons to Buy

  • Comfortable
  • Durable
  • Warm when layered
  • Cool worn alone
  • Smell fighting wool

Reasons to Avoid

  • Lacks support where you'd like it

  Taft Lodge on the Long Trail (Vermont) Long a fan of Smartwool layers in winter, I spent this summer testing some of their gear that works well in warm weather. Along with the Merino Boxer Brief, which I wore almost every mile of the season, I also spent some time wearing Smartwool's Classic All-Season Merino Base Layer Bottom. Light in the pack and extremely versatile on the body I found these bottoms to be worth carrying on trips long and short. There is also a women's version of this.

Read more: Smartwool Classic All-Season Merino Base Layer Bottom review (1)

Black Diamond Solution 150 Merino Base 3/4

user rating: 4.5 of 5 (1 review)

Black Diamond's Solution 150 Merino Base 3/4 is a lightweight, polyester-reinforced merino wool base layer. Cool enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. Stretch fabric gives a comfortable fit even on a slim frame and dries a little faster than 100 percent merino. 3/4 length works with high plastic cuff ski boots.

Reasons to Buy

  • Comfy fit and feel
  • Light base layer for intensive activity
  • Also good for cold-wet days in summer
  • Lightweight in the pack
  • 3/4 length works with tele and rando boots and saves a little weight

Reasons to Avoid

  • Polyester core may shed microplastic fibers in wash water
  • No long sizes

(Preliminary review based on the first month of use) Black Diamond’s Solution 150 Base shirts and long underwear are lightweight, polyester-reinforced merino wool base layers. They are light enough to wear under light shell clothing for high intensity activity at around-freezing temperatures without overheating, but easily layered over for use in colder conditions or at lower intensity. BD has supplied me with both a crew neck top and ¾ length bottoms for testing. Much of what I have to say about the one will apply to the other and so may be duplicated in both reviews.  The Solution 150 lineup also includes a full length bottom, and all three variants are also available in women's versions.

Read more: Black Diamond Solution 150 Merino Base 3/4 review (1)

Top Base Layer Bottom / Fleece

Patagonia R1 Pants

user rating: 5 of 5 (2 reviews)

This is a fairly warm synthetic base layer, loose enough to serve as a mid-layer. I recommend wearing alone for cooler weather and beneath a shell or insulated pants in really cold weather. The newer version has two hand pockets rather than a back pocket and is sized even more loosely than past versions—including looser cuffs at the bottom. New ones also have a drawstring, a plus.

Reasons to Buy

  • Durable—a quality base layer
  • Warm
  • Does well at pulling moisture away from you
  • Drawstring

Reasons to Avoid

  • Pockets don't zip
  • Some might prefer a tighter fit

The R1 bottom is kind of like a versatile pair of outdoor sweatpants. They are thick enough to wear alone in fairly cool weather if you are active, and they are very warm if you wear them under a shell. On cooler summer nights, I'll often put them on as the temperature drops in camp.     FIT: The fit on these used to be pretty average. They have enough room and plenty of stretchiness to wear over a tight, lightweight base layer or running tights if needed. The current version is sufficiently loose that they wouldn't be a great deep cold base layer, but they now layer better over a base layer bottom.

Read more: Patagonia R1 Pants reviews (2)

Patagonia Capilene 3 Midweight Bottoms

user rating: 5 of 5 (1 review)

Excellent base layer bottoms.

Reasons to Buy

  • Comfortable
  • Warm
  • Durable

I was looking for a comfortable pair of base layer bottoms to keep me warm under my work dress pants. These things were perfect. I am about 5'11" 180 lbs with a 33/34 inch waist and I think the medium is a perfect fit. These bottoms are form fitting but not so constricting where it feels too tight or decreases my mobility. The material is very soft to the touch and stretchy. I have read stories about other base layer materials getting ripped by toe nails when people have tried to put them on, but this material has so far been very durable and doesn't seem prone to getting ripped by a toe nail snag.

Read more: Patagonia Capilene 3 Midweight Bottoms review (1)

Outdoor Research Alpine Onset Bottoms

user rating: 3.5 of 5 (1 review)

The Outdoor Research Alpine Onset Bottoms are soft on the skin and easy to maneuver in. They're best when on the move in cool/chilly temps like hiking or bike riding, and they are flexible enough for highly active pursuits.

Reasons to Buy

  • Soft
  • Adaptable
  • Controls odors
  • Bonus: Very comfortable to sleep in
  • OR's Infinite Guarantee for lifetime of product

Reasons to Avoid

  • Short inseam, lacking a long option
  • Not warm enough below freezing

Conditions and Temperatures:I tested the Alpine Onset baselayer bottoms, along with their crew top counterpart, the Outdoor Research Alpine Onset Crew top. These items are part of Outdoor Research's Alpine Onset collection, which includes an array of men's and women's layers. I’ve worn the OR Alpine Onset Bottoms for five months through the fields and forests of central Pennsylvania while hiking, camping, hunting, mountain biking, and for general everyday purposes. Temps have ranged from -18°F to 60°F (-28°C to 15.5°C), but based on my experiences, these baselayer bottoms are best suited for at or above freezing temps (32°F/0°C or above).

Read more: Outdoor Research Alpine Onset Bottoms review (1)

More Reviews of Base Layer Bottoms

Trailspace reviewers have shared 59 reviews of 50 different base layer bottoms.

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Other Types of Base Layers and Underwear

Find more base layers and underwear reviewed in these related categories:

Base Layer Tops

Boxers, Briefs, Bikinis

Arm and Leg Sleeves

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