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REI Co-op Merino Midweight Bottoms Review

A simple and comfortable merino option
rei co-op merino midweight bottoms long underwear review
Credit: REI Co-op
Price:  $80 List
Manufacturer:   REI Co-op
By Roland Mott ⋅ Review Editor  ⋅  Nov 19, 2019
  • Warmth - 30% 6.0
  • Breathability - 30% 7.0
  • Comfort and Fit - 30% 7.0
  • Durability - 10% 5.0

Our Verdict

Made with 200 grams of fine 100% Merino wool, the REI Co-op Midweight Merino Bottoms are soft against the skin and offer all of the benefits of Merino wool - great thermoregulation, breathability, wicking ability, and all day comfort. These bottoms didn't stand out above the other Merino layers but offer quality and straightforward bottoms for the everyday user. A great weight to carry you through all four seasons of adventures. Summer backpacking trips, winter hut trips, fall canoe trips, these are a great pair of bottoms for just about anything. Layer accordingly, and you're good in freezing cold and cool spring evenings.
Not very durable
Tend to stretch

Our Analysis and Test Results

The REI Co-op Midweight Merino is a comfortable and quality pair of 100% Merino wool bottoms that do well in cool to cold conditions.

Performance Comparison

rei co-op merino midweight bottoms long underwear review - a great simple midweight merino layer
A great simple midweight merino layer
Credit: Roland Mott


These bottoms are a typical midweight bottom in every way. They can keep you warm in frigid temperatures when paired with an insulated pair of bottoms or serve you well alone on a warm summer evening in the backcountry. They do a good job of regulating body temperatures through varying temperatures and levels of activity, and the naturally hydrophobic Merino fibers do a great job at wicking sweat and keeping you dry so that you can stay warm once you stop moving.

rei co-op merino midweight bottoms long underwear review - for those cold desert bivies, the midweight merino is a solid...
For those cold desert bivies, the Midweight Merino is a solid companion.
Credit: Roland Mott


Like any quality Merino wool, these are going to breathe well, dumping heat on the uphill battles and wicking sweat so that when you start the downhill cruise, you're not putting wet bottoms into a freezing wind tunnel. These bottoms did a great job of keeping us dry when we were a hot sweaty mess trail running or skinning under blue skies.

rei co-op merino midweight bottoms long underwear review - searching for goods, the rei merino midweight is great for cold and...
Searching for goods, the REI Merino Midweight is great for cold and cool outings alike.
Credit: Kricket Servis

Comfort & Fit

These bottoms generally fit really well, and the Merino is super cozy next to skin — not itchy at all. They have nice long legs, a simple seam pattern that stays out of the way and a crotch that has a little sag but nothing too offensive. The stretchy Merino wool fits all types and thickness. If you have skinny legs, the legs run a little loose, but not baggy. Still snug enough to layer under a pair of jeans without them bunching up badly. The waistband is sewn on and doesn't have any added features to make it extra comfortable. The tag in the back of the waistband is itchy if worn next to the skin. Like most Merino layers, these bottoms do tend to stretch out during use, especially anything active. They regain their original dimensions after a wash.

rei co-op merino midweight bottoms long underwear review - thawing out after a long day of fun in the snow. a snug and...
Thawing out after a long day of fun in the snow. A snug and comfortable fit.
Credit: Jo Savage Photography


Merino isn't always known for its durability, and these are 100% Merino. They stretch out after active use, and they don't hold up to abrasion well. Our abrasion test burnt a hole through these pretty easily. That isn't to say that if you take care of them and don't drag them across pavement and granite like we did, these bottoms can last you a good long while. These bottoms aren't going to be as durable as some of their synthetic counterparts. While they're not the most fragile, they are far from the most durable.

rei co-op merino midweight bottoms long underwear review - the abrasion test results.
The abrasion test results.
Credit: Roland Mott


Considering the price of other full-Merino options in our review, the price of these are very much middle-of-the-road. Not the most valuable base layer based on performance, but if you are looking for a midweight layer with an all-natural knit, these are certainly worth their weight in warmth.

rei co-op merino midweight bottoms long underwear review - good versatility breathing well on the uphill and keeping you warm...
Good versatility breathing well on the uphill and keeping you warm on the downhill, the Midweight Merino from REI is a great all-around layer that costs a bit less than its comparable competition.
Credit: Adam Zagorski


A great weight and a simple and comfortable bottom that works well across a spectrum of activities and temperatures. 100% Merino wool allows for great thermoregulation and breathability. Not the most impressive of the bunch but a quality pair of blue-collar bottoms.

Roland Mott
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