10 Best Merino Wool Base Layers 2026 in the United States

The Merino.tech Merino Wool Base Layer Mens Set is designed to meet the needs of those looking for reliable thermal underwear. Its midweight fabric at 250 g/m² strikes a good balance for various conditions, making it suitable for outdoor activities like hiking or simply for warmth during colder months. The set includes a top and long johns, which is a convenient option for anyone in need of a complete layering solution.

One of the standout features is the fabric's micron count of 17.5, which indicates the use of superfine merino wool. This not only ensures a soft, non-itchy feel against the skin but also enhances comfort for all-day wear. The moisture-wicking properties of merino wool are a significant advantage, as they keep you dry by pulling moisture away from the skin while also providing natural odor resistance, making this set ideal for active individuals.

The base layer requires careful washing and drying; hand washing and laying flat to dry is recommended to maintain its quality, which may not be convenient for everyone. Additionally, while the midweight option is versatile, those who require extremely lightweight or heavyweight options need to choose accordingly based on their specific activity levels and climate. The inclusion of hiking socks is a nice bonus, adding value to the package. The price point may be on the higher side compared to cotton alternatives, which might deter some buyers looking for budget-friendly options.

The Merino.tech Merino Wool Base Layer Women Set is designed for women seeking a comfortable and functional base layer for various activities. One of its standout features is the midweight fabric, weighing 250 g/m², which strikes a good balance between warmth and breathability. Made from 100% superfine merino wool with a micron count of 17.5, it promises a soft feel and no itching, making it suitable for all-day wear.

The set includes both a top and leggings, enhancing its value, especially with the added bonus of merino wool hiking socks. Users will appreciate the moisture-wicking properties that help keep them dry and the natural odor resistance, making it ideal for outdoor adventures or extended wear.

There are some considerations to keep in mind. The care instructions suggest hand washing and air drying, which could be inconvenient for some users accustomed to machine washing. Additionally, while the set is breathable, the midweight option might not be warm enough for extremely cold conditions compared to the heavyweight alternative.

The Smartwool Women's Classic Thermal Merino Base Layer Crew is a solid choice for anyone looking for comfortable and breathable merino wool layering for outdoor activities like hiking, skiing, or cycling. Its fabric blends merino wool with polyester, which helps it dry faster and adds durability. The fabric is lightweight and features mesh zones to improve breathability, making it versatile for cool to warm conditions.

The regular fit offers enough room to move without feeling bulky, which is great if you want freedom during physical activity. Flatlock seams reduce chafing, so it feels comfortable even during longer wear. Merino wool is known for managing temperature well—it keeps you warm when it's cold and cool when it's warm—and this base layer benefits from that natural feature. It also resists odors, so you can wear it multiple times between washes without it smelling.

This base layer is a comfortable, breathable, and versatile option for active women who want reliable odor resistance and easy care, especially for mid-season outdoor adventures.