Icebreaker Quantum III Hoodie Review

Merino clothing is well known in the world of outdoor adventure sports thanks to its ability to provide warmth, breathability, and odor-resistance.

It’s also a natural material, which is becoming more and more appealing as consumers look for ways to transition away from plastics and other synthetic materials.

In this article, I review the Quantum III Hoodie, the latest version of Icebreaker’s technical mid-layer.

How we conducted this review

Kosciuszko National Park

We took the Quantum III as our primary mid-layer for a 5 day hike in the Kosciuszko National Park in late November.

The conditions were perfect for testing this type of product with temperatures ranging from sub-zero through to mid-teens.

We used the Quantum III for high-intensity activities such as climbing several of Australia’s highest peaks, as well as sitting around in the cold in the evening, and even for sleeping in freezing conditions. 

Icebreaker were kind enough to provide the product for review but all opinions are our own.

Who is the Quantum hoodie for?

The Quantum III is a versatile high-performance top suitable for a wide range of activities.

While it is primarily designed for high-intensity mountain activities such as hiking or skiing, the modern design makes it perfectly suitable for casual wear. The zip pockets, hood, and odor control also make this an excellent option for travel.

The weight of the Quantum III is 270 grams per metre, which sits in Icebreaker’s “Midweight” category.

Icebreaker state that this weight is “best suited for cold conditions” but keep in mind that this is a mid-layer so you’ll still want warm layers underneath and on top if you expect to be in winter conditions.

First Impressions

This hoodie is marketed as slim fit, but as with most Icebreaker tops, you can always go a size up for a more relaxed fit. I usually wear a size large top/t-shirt and did the same with the Quantum III.

The material itself is soft and comfortable and the hoodie has a nice weight to it.

The fit is pretty much exactly what I’m after for hiking and general outdoor activities. It has enough space for layers underneath and is still relaxed enough to wear casually.

I was also very pleased with the length. I’m 6’2” and the length on the size L is perfect. It would be suitable for activities where extra coverage is important such as skiing or cycling.

In fact, Icebreaker mention in the product description that the Quantum III has a “drop tail hem for added coverage”.

Key Features

Regulates body temperature

Temperature regulation was a big factor on this particular hike as we were alternating between climbing peaks in the scorching alpine sun and walking through shaded valleys with bitterly cold winds.

Having a mid-layer that I could keep on throughout the day was a big plus, and I didn’t find myself overheating as can often happen with synthetic layers. 

The Quantum III was thankfully comfortable enough to sleep in on a couple of sub-zero nights. The temperature regulating properties of merino were of great benefit here also, and meant I stayed warm but didn’t overheat inside my sleeping bag.

This isn’t necessarily what this product is designed for but it’s always good to have your mid-layers available for sleeping if temperatures drop.


One of the main selling points of merino is that it’s naturally odor-resistant. I’ve owned enough merino garments over the years to know this isn’t just a marketing gimmick.

Testing the Icebreaker Quantum III

Sure enough, the Quantum III performed well in this department with little noticeable odors after 5 days of use.

I will note, however, that this tends to be more of an issue with base layers or socks that are in constant contact with your skin. If I could only choose one layer to be merino, it would be my base layer.

On this particular hike, I packed a synthetic performance top from another popular brand and it performed very poorly in terms of odor resistance in comparison to the Icebreaker gear.

Fitted hood

The hood on the Quantum III is soft and comfortable and was a welcome feature during evenings at camp or cold nights in the tent.

Note that while the hood is fitted, it isn’t adjustable.

3 x Zippered pockets

The Quantum III features one zippered chest pocket and two zippered hand pockets. 

I found the chest pocket to be the best place to store my phone, as the zippered pockets are located in the same place as the pack waist belt.

The zips all appear high quality and I’ve experienced no issues with them so far.


Overall, I’ve been very impressed with so far with the Icebreaker Quantum III. It’s comfortable, fits well, and has been excellent at providing warmth as a mid-layer in cold conditions but not overheating during intense exercise.

In my experience Merino does tend to get small holes after a few years of use so will be interested to see how this holds up but so far so good.

View the Quantum III at Icebreaker.

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The Adventure Lab

At The Adventure Lab, our goal is to provide high-quality, actionable information and advice to help you plan for your next adventure. Our team of writers consists of professional mountain guides, personal trainers, exercise physiologists and more.