10 Best Merino Wool Base Layer Pants 2024

Last Updated on 27/08/2023

Best Merino Wool Base Layer Pants

What Are the Best Merino Wool Base Layer Pants?

Whether it is below freezing outside or just extremely frosty, nobody likes to shiver. The best base layers are your first line of defense to capture and hold onto your body heat when Autumn and Winter set in. In this guide, you will learn which are the warmest and most breathable merino base layer bottoms available today.

Unless you snowboard or ski, then it is very unlikely that any of the pants in your closet have insulation in them. Not to worry because this list of the best Merino wool base layer pants is your ultimate guide to keeping your legs warm. To keep your privates warm, check out this list of the best merino wool underwear

Layering up is far more effective than one super warm layer, and it is also far easier to regulate the temperature by adding and removing layers as you start to warm up. When you are active, you might only need a base layer top and t-shirt to stay warm without overheating. But once you stop moving, you will need to put on a coat, and this is when your legs start to get cold.

Having some of the best merino wool base layer pants on will ensure you stay warm and comfortable while hiking and camping. For total warmth and comfort, check out our top 10 Merino Wool Base Layer Tops.

Top 10 Merino Wool Base Layer Pants

Icebreaker Men’s Everyday Leggings

Icebreaker Men's Everyday Leggings

As the name suggests, the Icebreaker Men’s Everyday Leggings are some of the best merino wool base layer pants for everyday use. Made from lightweight and breathable 100% Merino wool, you can wear these for all kinds of outdoor sports as well as just lounging around base camp.

A gusset on the crotch and seat allows for total freedom of movement with a functioning fly and no center-back seam for a comfortable fit. The natural odor prevention of Merino wool means you can wear these pants day after day without feeling self-conscious. The brushed waistband feels great underneath other layers, and the flatlock seams add to the impressive comfort and durability of the Everyday Leggings.

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WoolX Merino Wool Base Layer Pants Midweight

WoolX Merino Wool Base Layer Pants Midweight

The WoolX Merino Wool Base Layer Pants are made from 100% Australian Merino Wool and are midweight for a wide range of temperatures and activities. As soft as cashmere but more durable, WoolX merino wool is hypoallergenic and non-itchy for the best next to the skin comfort base layer.

The midweight material is ideal for staying warm while active in cold temperatures without overheating. Breathability, odor resistance, and moisture-wicking properties make these base-layer pants perfect for hiking.

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Smartwool Men’s NTS Mid 250 Bottom

Smartwool Men's NTS Mid 250 Bottom

The Smartwool Men’s NTS Mid 250 Bottom is for the coldest days when a single layer of trousers just isn’t enough. Machine washable and tumble dryable, these merino wool base layer pants are easy to care for and anti-microbial for multi-day use. The fit is slim and has flatlock seams with interlocking knit construction designed for maximum comfort and minimal chafing.

Smartwool has been around for over 20 years now and is trusted by many long-distance hikers on the AT and PCT for its warmth-to-weight ratio. A top performer we can recommend for backpacking, winter warmth, and outdoor activities in the cold.

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Icebreaker Men’s Apex Leggings

Icebreaker Men's Apex Leggings

The Icebreaker Men’s Apex Leggings are luxuriously soft and warm base layer pants for active pursuits and just generally keeping your legs warm and your body temperature up. The Apex Base Layer Top is our top pick for the upper half, and it is hard not to award the same result for these pants. They are midweight and thicker than most merino base layers without being too warm for things like hiking.

The fit is slim and stretchy, with a functioning fly and gusset for comfort and mobility. These really are a great option for your kit bag.

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Minus33 Merino Wool Men’s Kancamagus Midweight Bottom

Minus33 Merino Wool Men's Kancamagus Midweight Bottom

The Minus33 Merino Wool Men’s Kancamagus Midweight Bottoms are made from 100% Merino wool which traps a layer of warm air next to the skin. Available in many color choices, including camo, you can blend into your surroundings or stand out from the crowd.

A classic midweight base layer bottom you can wear day after day that wicks moisture and is odor resistant. Amongst other features, these pants have a UV rating of UPF 50+, flatlock seams, stretch cuffs, tagless labeling, and are fire-resistant. Popular with hunters and outdoorsmen around the world, you won’t be disappointed with these long johns.

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Merino 365 Men’s Slim Baselayer Pants

Merino 365 Men's Slim Baselayer Pants

The Merino 365 Men’s Slim Baselayer Pants are just like your favorite pair of comfy joggers apart from being super lightweight and slimmer. While these pants are by no means baggy, they do fit slightly looser than other baselayers if that is something you are looking for.

The Merino 365 brand is well known for making quality baselayers from the best materials, and you can definitely trust the quality. These are great for wearing on cold daytime adventures, and if you don’t have the warmest sleeping bag, then wearing these on a night will keep your legs nice and warm for sure.

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Ibex Merino Woolies 1 Bottom

Ibex Merino Woolies 1 Bottom

The Ibex Merino Woolies 1 are a lightweight, high Merino wool content rib-knit base layer bottom for all-day comfort. With a nylon core wrap for extra durability, you get all the benefits of Merino wool and some of the benefits of synthetic materials, like faster drying times.

The one-and-a-quarter-inch waistband is comfy and robust, allowing for double-panel construction and fly opening. The fit is very good, and the ankle cuffs are long to tuck inside your socks, which makes them great for skiing/snowboarding.

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Icebreaker Merino Men’s Winter Zone Leggings

Icebreaker Merino Men's Winter Zone Leggings

The Icebreaker Merino Men’s Winter Zone Leggings are made from 260 g/m² midweight fabric with optimized venting panels for added breathability. The technical panels on the inner thigh and around the knees support the most intense outdoor pursuits where you may be wearing waterproof layers on top.

Made from a blend of Merino wool and synthetic fibers, you get a really soft and stretchy finish that wicks moisture and dries out very fast, which is what you want when you are in the thick of it. Don’t let the low weight and breathable panels fool you, though; these base layer pants will help to keep you warm in very cold conditions.

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ColdPruf Classic Base Layer Pants

ColdPruf Classic Base Layer Pants

The ColdPruf Classic Base Layer Pants are made from a single layer of 100% Merino wool with a Jersey knit. They are snug-fitting but incredibly stretchy to provide the most effective base layer under your other clothes.

The waistband is comfortable and sits smoothly under belts, and doesn’t slip down, holding them up very well. There are gussets around the crotch to prevent chafing during active pursuits, and the contours work well to allow total freedom of movement. I really like these to wear underneath another base layer as they fit so snugly and stretch so well, but they also work well on their own.

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Helly Hansen Men’s HH Wool Base Layer Pants

Helly Hansen Men's HH Wool Base Layer Pants

The Helly Hansen Men’s HH Wool Base Layer Pants are their only 100% Merino wool base layer pants and are classed as midweight. All other Helly Hanson Merino base layers are made with a lifa blend which has its benefits, but overall, I would much rather have these.

With flatlock seams on the inside, there is no rubbing or chafing, and the fabric feels very light. They are available with or without a fly opening at the front, and the legs are nice and long for taller people. Maybe not my first choice for the best merino wool base layer pants, but you can’t go wrong with a pair of these.

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merino base layer pants

Guide to Merino Wool Base Layer Bottoms

What should you look for when buying base layers online? Here are some of the basic things you should know about base layer bottoms:

Wool Content

Merino base layer pants are either 100% merino wool or blended with other synthetic fibers to improve certain characteristics. 100% merino thermal pants emphasize all the amazing qualities of the wool, whereas blending with materials like elastic, polyester, or nylon can improve durability, elasticity, and fit. We don’t mind merino wool blends for our bottoms, as extra durability is sometimes needed.

Merino Yarn Weight

When looking for merino long John’s, you will often see a number like 120 or 240 GSM in the product name. This refers to the thickness of fibers that are used, and GSM stands for grams per square meter. Base layer bottoms made from merino wool will typically be lightweight at between 110 – 180 GSM or midweight at 180 – 300 GSM. You will rarely see anything thicker as it would be too warm.


If you are a guy, then maybe you want a functioning fly opening, but beyond this, you should look at the shape of the crotch as well as how deep it is from the waist. Base layer bottoms can be worn fairly high up without giving you a wedgie, but ideally, they will sit at your trouser line, so you don’t want a big baggy crotch. We have never seen thermal bottoms with a diamond-shaped crotch, although that is something we would be interested to see.


To make the most of your money, you can look for merino wool blends that are typically cheaper than 100% merino wool. They are almost as warm and offer all the same benefits just to a slightly lesser extent. You can expect to pay anywhere from $20 on sale to over $100 for the premium merino thermals.

base layer hoodie top and pants merino

Is Merino Wool Good for Base Layer Pants?

Merino wool is the perfect material for the base layers of pants for many different reasons. The first reason is that they thermoregulate your temperature, which means they keep you warm when it’s cold but don’t overheat when you warm up.

They are breathable, moisture-wicking, and odor-resistant, which means that when you sweat, you dry out fast and don’t smell like BO. Merino wool is also very lightweight and stretchy, which means you never feel restricted and can layer them easily.

Are Long Johns the Same as Base Layers and Thermal Underwear?

Long johns are exactly the same thing as base layers and underwear; however, long johns typically mean a two-piece set of both bottoms and a top instead of just a single piece. Long johns can also be used as full-length underwear that you wear without anything underneath. An interesting fact about long johns is that they are named after a 19th-century boxer named John L. Sullivan, who wore this type of garment in the ring.

How Tight Should Base Layer Bottoms Be?

Base layer pants and thermal underwear bottoms should be word next to the skin without being too baggy or too tight. The key is to find the balance between loose and close-fitting long johns that trap warm air next to your skin without applying any kind of compression. Merino is very stretchy, but we have a guide on how tight base layers should be if you want to learn more.


We hope you found these Top 10 Best Merino Wool Base Layer Pants useful, and feel free to leave your comments below.

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This article has been written and/or edited by Andrew N. 20+ years of hiking, mountaineering, and camping experience, with access to all the latest outdoor gear.

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