Icebreaker Merino 200 Oasis Bottoms Review

Icebreaker has consistently produced excellent 100% merino base layers for a long time — the 200 Oasis bottoms are no exception, living up to their exceedingly high standard of quality wool. These are certainly designed as a slim-fit, athletic pair of long underwear, proving themselves in terms of warmth and breathability. On chilly morning runs, and early morning wake-ups on backpacking trips, we were happy to slide on this stylish pair of long underwear for our active adventures.

Although these are not in the top selection of our review, you will notice that they performed very well across the board, they just simply were not exceptional in any one category. The merino wool is not as plush as similar competitors, and the brushed, jersey-feel of the fibers left us itchier in these tight-fitting bottoms when our legs warmed up. While our lab testing suggests impressive abrasion-resistance, a quick snag of a branch on a trail run put a hole in these leggings.

Performance Comparison

Walking a tightrope between light- and midweight to span the seasons.

Photo: Aaron Rice

Warmth

Icebreaker lists these 200-weight bottoms as a lightweight baselayer. Despite the fact that their fabric weight would throw them in more at the low-end of our midweight options, we would tend to agree with their ranking. For the weight, these are incredibly thin, and their ability to retain warmth reflects that. We were much more comfortable running in these in the cool, early-dawn conditions of the fall than we were crawling out of our sleeping bag on a chilly, alpine morning.

The 200 Oasis is definitely designed with fast-paced, highly aerobic activity in mind. Just like other 100% merino wool knit layers, this pair of bottoms does a great job with thermoregulation — just as long as you keep your heart rate up. We would opt for these for long days of spring ski touring but look elsewhere for some extra warmth during the coldest days of winter.

Just the right amount of solid, 100% Merino to fight off the early-morning chill on fall backpacking trips.

Photo: Jill Rice

Breathability

As noted above, these are thin for their weight — but as a result, they breathe very efficiently. Merino wool is the natural king of moisture wicking, and the 200 Oasis bottoms are 100% merino. Thanks to a tight fit, these do a great job of pulling that moisture away from your body, keeping you dry during highly aerobic activity.

We enjoyed them for trail running in cool to cold weather for this very reason. While full-wool has the benefit of moisture wicking, it does not evaporate that moisture nearly as quickly as their polyester companions. This is the classic conundrum between natural and synthetic fibers — and the 200 Oasis bottoms fall victim to this, just not evaporating sweat quite as quickly as synthetic, or some even synthetic-blend competitors.

These bottoms are more flexible than we are, providing an impressive amount of breathability for their stated fabric weight.

Photo: Jill Rice

Comfort and Fit

The 200 Oasis may be a full-merino knit, but it doesn't have the same soft, cushy feeling of the other 100% merino layers in our review. The extra-slim fit contributes to the slight itch we experienced when wearing it next-to-skin — this sensation disappeared during most activities but didn't leave us wanting to continue wearing them around the house once we returned from the day's adventure.

These are truly a classic base layer fit. The 200 Oasis bottoms offer a slim, athletic cut through the legs, with slightly extra room in the seat, all book-ended by tight ankle cuffs and a hip-hugging waistband. The activewear-inspired look of these bottoms is evident in their name — Icebreaker markets them as "leggings," rather than long underwear.

Fit of the Icebreaker Merino 200 Oasis: slim, European-cut through the majority of the legs, with articulation in the seat to expand and offer room for a more ample buttocks. Our tester is 5'10", 160lbs wearing a size medium.

Photo: Jill Rice

Their cut fits a skinny, athletic frame incredibly well — where our head tester often suffers from the saggy-butt syndrome, these were form-fitting through the seat. Additionally, a well-placed, articulated seam a few inches below the waistband is a thoughtful design consideration. This seam cuts off the leg at the top of buttocks and would offer extra space for those with more-ample bottoms to fill out these pants without increasing undue constriction around the waist.

Thoughtfully articulated seams provide an slimmer fit for those without a butt, and ample room for expansion for those with larger ones.

Photo: Jill Rice

Durability

Durability is often the double-edged sword of full-merino base layers. Although the Oasis is listed as a garment weighing 200 g/m², the material feels much thinner than the fabric weight suggests. As a pair of long underwear that does a great job of pulling double duty as a running tight, we were worried about the potential for ripping the thin wool. Sure enough, on our second trail run in these bottoms, we accidentally snagged a branch of a sage bush, which put a small hole right through the fabric.

Despite our field-experience, our lab testing would suggest an impressive fabric durability. After our aggressive abrasion test, the 200 Oasis hardly presented any signs of scuffing beyond a few fluffs of wool that scraped off of the face fabric — it certainly didn't come close to producing a hole, or even a thin spot in the fabric.

An unfortunate consequence of trail running, but we're not surprised that the rather thin wool is susceptible to puncture wounds.

Photo: Jill Rice

Value

These bottoms have the added benefits of an all-natural build, and offer top-quality warmth and breathability in an athletic package. The 200 Oasis bottoms do have a stylish, yoga-inspired look, and can easily pull double-duty as running leggings, adding to their value.

This bottoms do a nice job of balancing just the right amount of warmth and breathability, making them a great backpacking companion on chilly alpine mornings.

Photo: Jill Rice

Conclusion