In the world of skiing, performance and enjoyment do not depend solely on the quality of the skis or the technology of the boots. They start much closer to the body. Although often overlooked, the thermal layer is the key to comfort on the mountain. It determines heat management, moisture wicking, freedom of movement and, ultimately, the ability to ski for long periods without discomfort.
At I Love Ski, we often remind ourselves that being warm does not mean sweating, and staying dry is the key to fully enjoying a day on the slopes, whatever the conditions. With this in mind, natural fibres (and merino wool in particular) now play a central role. The brand Icebreaker, a pioneer in this field, is one of the best examples of this.
We have tested two flagship models from Icebreaker’s merino wool baselayer range, designed for complementary uses in skiing and mountaineering:
– the 360 RealFleece for women,
– the 260 ZoneKnit for men.
Two different approaches to thermal insulation, but the same philosophy: supporting the body during exercise, without ever forcing it.
The thermal layer: the cornerstone of the three-layer system in skiing
Before going into detail about the products tested, it is worth remembering that, in skiing, thermal management is based on the three-layer principle:
The first layer, called the “base layer”, is in direct contact with the skin. Its function is essential: to regulate body temperature and wick away moisture. An inadequate base layer (too thick, not breathable enough or unsuitable for the intensity of the activity) quickly causes cooling, a feeling of dampness and, subsequently, lasting discomfort.
Unlike traditional synthetic materials, merino wool has a unique ability to insulate even when wet, while naturally limiting odours. This is precisely what makes it an ideal ally for skiing, where effort and rest are constantly alternating (chairlift rides, demanding descents, breaks on the terrace or at the summit).
Icebreaker and merino wool: a benchmark that has become the standard
For more than twenty years, Icebreaker has developed its expertise around merino wool selected for its fineness, strength and thermal performance. The New Zealand brand has greatly contributed to democratising the use of this natural fibre in winter sports, offering technical products capable of competing with (and often surpassing) synthetic fabrics.
The two models tested are fully in line with this approach: no compromises between performance, comfort and durability.
Icebreaker 360 RealFleece Women’s: controlled warmth for long days on the slopes
The 360 RealFleece for women, tested in its beige version with a pink zip, sits halfway between a thermal layer and a lightweight mid-layer. Made from brushed merino wool (290 g in size M), it has a fleece structure without synthetic fibres, a key feature for female skiers who value comfort and breathability.
On the ground, the first sensation is immediate: you feel the warmth as soon as you put it on, but without feeling stifled. The fabric adapts naturally to the body while remaining highly flexible. In downhill skiing, on cold but sunny days, RealFleece provides remarkable insulation, particularly during static phases (queues, lifts, breaks) or to limit the impact of wind on thermal comfort.
During the most active sequences, merino wool fully performs its role as a thermal regulator. Sweat is absorbed and gradually wicked away, preventing the “chilling” effect so common with lower-quality fabrics.
This model is clearly aimed at female skiers looking for a warm, comfortable and versatile garment that can guarantee lasting thermal protection throughout a day of skiing, without the need for multiple layers. It is also ideal for other activities at the resort: walks, snowshoeing, gentle skiing or outdoor activities after skiing.
Design and quality
The beige “Sunstone” colour with contrasting pink zip adds a feminine and modern touch. The finish is very neat (lined hood, elasticated cuffs, clean seams), as with all Icebreaker products. The high-quality merino wool is naturally antibacterial and durable, ensuring the garment will last a long time.
Icebreaker 260 ZoneKnit for men: thermal precision for active skiers
Unlike the “capsule” logic, the 260 ZoneKnit for men, tested in red and burgundy, takes a much more physiological approach to the thermal layer. In this case, Icebreaker opts for precise body mapping, with different fabric zones depending on heat and ventilation needs.
In areas exposed to the cold (torso, shoulders), the density of the merino wool guarantees excellent insulation. Conversely, in the armpits and back, more breathable panels promote heat and moisture wicking. The result is particularly convincing in extreme skiing, freeriding or assisted cross-country skiing, where intensity varies considerably.
On the ground, this ZoneKnit stands out for its thermal stability. Even during prolonged exertion, the feeling of overheating is minimal. The snug fit accompanies your movements without ever compressing, and the flat seams reinforce comfort under a technical jacket.
This model is designed primarily for dynamic and athletic skiers who are looking for a base layer that can keep up with them without slowing them down. It will be especially appreciated by those who sweat easily and want to stay dry all day long.
These tests confirm a reality that is often underestimated: choosing the right thermal layer radically transforms the experience on the slopes. A good base layer reduces fatigue, prevents uncomfortable feelings of cold and allows you to enjoy every descent more.
