10 Best Long Underwear For Women 2026 in the United States

The Merino.tech Merino Wool Base Layer Women Set is a great choice if you're looking for comfortable, warm long underwear crafted from 100% superfine merino wool. This midweight set (250 g/m²) strikes a nice balance between warmth and breathability, making it suitable for cooler weather activities like hiking or layering in winter. The fabric is soft and fine enough to avoid itchiness, which can be a problem with some wool products. It’s designed to fit well without bunching or rubbing, though sizing and fit can vary slightly by body shape.

One standout feature is its natural moisture-wicking and odor-resistant properties, helping you stay dry and fresh during extended wear. The construction appears thoughtful, but hand washing and flat drying are recommended to maintain softness and shape, which may require a bit more care than synthetic alternatives. The package even includes merino wool hiking socks, adding good value.

If you want a natural, breathable base layer that manages moisture effectively and resists odors, this set is a solid option. For those who prefer machine-washable or lighter-weight base layers for high-intensity activities, exploring other choices might be beneficial.

The Merino.tech Merino Wool Base Layer Women Set consists of a top and bottom made from 100% superfine 17.5-micron merino wool, plus a beanie. This set is midweight, with a fabric weight of 250 g/m², providing good warmth without being too heavy. The natural properties of merino wool make this set highly effective in moisture-wicking and odor resistance, keeping you dry and fresh throughout the day.

The material is also breathable, helping to regulate your body temperature, which is beneficial for year-round use. The fit is designed to be comfortable for daily wear, with the fabric being soft and non-itchy. However, the set requires special care; it should be washed on a delicate cycle and laid flat to dry, which may be inconvenient for some users.

Additionally, imported origin could imply a higher price point. This base layer is ideal for women seeking comfortable, versatile, and high-performance long underwear, especially those who spend a lot of time outdoors or engage in active pursuits. The inclusion of a Merino Wool Beanie adds extra value to the purchase.

The Cuddl Duds Thermal Underwear set for women is designed to keep you warm and comfortable during cold weather with its brushed fleece lining and soft outer fabric. Made mostly of polyester with a bit of spandex, this set offers a good stretch that makes it easy to move around without feeling restricted. It’s lightweight at just under 15 ounces, which means it won’t feel bulky when worn as a base layer or even on its own for lounging.

The fit is modern and practical, featuring a thumbhole on the sleeves and a comfortable rise on the leggings, which helps with staying warm and adds convenience. The seams and construction appear smooth and tag-free, reducing chances of irritation during long wear. The fabric is designed to wick moisture away, so you stay dry even if you sweat a little, and it offers breathability to prevent overheating.

Additionally, the material blocks 50+ UV rays, which is a nice bonus if you spend time outdoors in winter. The fabric is mostly synthetic, which might not feel as natural as cotton to some users, and while it helps with moisture, it may not be as breathable as lightweight wool options. For softness, warmth, and ease of movement, the Cuddl Duds thermal set is a solid choice for women looking for a reliable, cozy base layer for cold weather or casual indoor wear.