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Icebreaker Oasis Review

The Icebreaker Oasis is a solid merino wool base layer that has several nice features, but also fails to keep wrists and lower stomachs protected due to its short lengths.
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Price:  $90 List | $62.93 at REI
Compare prices at 4 resellers
Pros:  Comfortable, good warmth for the weight, resists odors, dries quickly
Cons:  Average durability, limited layering ability, short sleeves and torso
Manufacturer:   Icebreaker
By Ross Robinson ⋅ Senior Review Editor  ⋅  Dec 19, 2016
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The Skinny

The Icebreaker Oasis re-entered the competition in our latest Men's Long Underwear Review. We couldn't resist getting our skin wrapped up in this comfortable merino wool fabric once more. On top of great comfort, this shirt also breathes exceptionally well and is relatively quick to dry. Throughout the testing period, though, our patience with the sleeves of this model became similar to this fabric — thin. They were constantly riding up our arms and camping out there until we pulled them back down. When cold air hit our bellies, we were reminded of this model's short torso, too. It's also not as versatile in layering combinations as several other products we tested. Our opinion of this product is still pretty high, but its score wasn't enough to snag any awards.

New Colors

Since we reviewed this top, Icebreaker replaced a few color options for the Oasis. The bright blue colorway we tested is no more, replaced by the black option pictured above. Performance-wise, this top remains unchanged.

October 2018

Our Analysis and Test Results

The Oasis by Icebreaker is a merino wool product offering mixed performance. For $90, you get a top with very soft and comfy fabric, superior breathability, and fast drying speed. Its major downfall, though, is its small fit; we liked the tightness but were disappointed by the short sleeves and torso that always had us pulling it down. It also wasn't as warm as several other models and didn't overwhelm us with high durability, either.

Performance Comparison

Reviewer Ross Robinson testing out the Icebreaker over frozen terrain above Lake Tahoe.
Reviewer Ross Robinson testing out the Icebreaker over frozen terrain above Lake Tahoe.


The 200 g/m² merino wool on the Oasis provides a moderate level of insulation compared with the others tested but weighs only 7.4 ounces. Its drop tail added further insulation. However, this top felt colder when moving due to frequent exposure of the wrists. The sleeves took every opportunity to slide up our forearms, granting chilly air unwanted access to our shivering skin. The short torso had similar problems. With longer sleeves and torso, this product would have scored higher in this metric.

Umm  yeah. The Icebreaker here  not really impressing.
Umm, yeah. The Icebreaker here, not really impressing.


Like the rest of the merino wool shirts in this review, this long underwear product performs above average in breathability. Give credit for this advantage to the superior warmth-to-weight ratio of this fabric over synthetics. This allows a top of equal warmth to be made of thinner material and predictably breathe better.

Comfort and Fit

There was a bit of love/hate going on with the Oasis. We were huge fans of its soft texture and loved the tight fit that hugged our chest. Supplemented with an asymmetric lens-shaped gusset under each arm, this model has great mobility.

This model flexes well enough to use when climbing  but again  the sleeves sliding back were an annoyance.
This model flexes well enough to use when climbing, but again, the sleeves sliding back were an annoyance.

We were less than impressed, though, with the sleeves and torso. We didn't enjoy the constant adjustments that accompanied any movements we made in this shirt. Pulling down the sleeves over our wrists, or the shirt bottom over our bellies, shouldn't be a constant chore with a quality base layer.

For a better fit in the sleeves and torso, you might want to consider sizing up. However, the chest area won't be as tight if you do this, which would, unfortunately, have a negative effect on this top's warmth and fit.

Drying Speed

In the speed test, from soaked to dry, this top dried faster than other models of comparable materials and fabric weights. When you combine this strong showing with merino wool's resistance to absorb water, or even feel wet, you have an even better performance.


Merino wool clothing needs to be handled carefully, and the Oasis is no exception. This top is susceptible to abrasion and should dry flat or on a hanger to avoid shrinkage. The fabric, however, will not absorb odors like a synthetic so it should not have to be washed as frequently; extending longevity. We saw no significant signs of wear after three months of regular use.

Ross Robinson hiking around the city of Arequipa in southern Peru  with the 6 000+ meter Chachani volcano in the background.
Ross Robinson hiking around the city of Arequipa in southern Peru, with the 6,000+ meter Chachani volcano in the background.

Layering Ability

The snug fit in the chest and underarms of the Icebreaker model didn't lend itself to layering on top of other layers. When we tried, it bunched up the first layers in the armpits and restricted mobility, as well as adding discomfort. It did perform well in the traditional base layer sense. Jackets and mid-layers on top of this shirt were no problem at all.

As the temperature dropped below 50°F  we were ready to reach for another layer.
As the temperature dropped below 50°F, we were ready to reach for another layer.

Best Applications

Layering comfortably under jackets and mid-layers, we like the Oasis as our first layer during adventures into cold and frigid environments. It's not a great choice for activities that involve lots of mobility in the upper body, as it doesn't stay in place well.


At $90, the Oasis costs close to other products that perform better across the board. We believe this model is a good product, but there are better options for the money.

We like some features of the Oasis  but prefer a little more performance from a $90 shirt.
We like some features of the Oasis, but prefer a little more performance from a $90 shirt.


The Icebreaker Oasis performed above-average in key metrics for base layers, namely breathability, drying speed, and comfort. However, the designed shortness of the sleeves and torso let to mild frustration as we continuously readjusted this top. We liked this product, but it wouldn't be our first option in the long underwear marketplace.

Ross Robinson