10 of the Most Comfortable Thermal Underwear for Women

If you aren’t looking to spend a lot on your thermals, check out Long Johns Set from Thermajane. This is a popular option on Amazon as it is very budget-friendly and is a suitable thickness to be worn under jeans, leggings, or snow pants, so they are pretty versatile.  They will keep you warm, and they are ultra-soft and comfortable.

You need to be careful with sizing on the Thermajanes and double-check the sizing chart of the manufacturer since the sizing isn’t super extensive, so the fit can be a little off if you fall outside average sizing.  You can get the Thermajanes in eight colors, the material is fleece-lined polyester, so it is durable and washes and wears well. Most women find this style to be a good deal that is comfortable to wear all day.

Since they are fleece-lined, they are quite thick, with the outside of the fabric being a little bit slick, so it doesn’t bind or bunch up with what you are wearing.

The Uniqlo HEATTECH Line of thermals is a popular option for many people to wear under regular clothes. They aren’t really warm enough for lengthy outdoor activities, but they are great to wear in the winter under a dress or casual outfit.

Uniqlo has different levels of thickness for their HEATTECH garments that may be more suitable for colder situations, but the best use is as a base layer to add a bit more extra warmth to your regular wardrobe. They are pretty lightweight and soft, so they are super comfy to wear.

The other great thing about the HEATTECH line is that they don’t add any bulk and are so thin (yet warm) they feel great against your skin and aren’t noticeable under your clothes.

If you are looking for a design that is a little bit more high performance that will keep you warm even on the nastiest winter days, you should have a look at the Women’s Capilene® Thermal Weight Bottoms. This popular base layer uses Patagonia’s Polartec® Power Grid® fabric that is an excellent insulator, and its HeiQ® Fresh technology that odor-resistant and super breathable. It is a perfect base layer if you spend a lot of time outdoors in the cold weather.

The Capilene bottoms are lightweight yet stay nice and toasty in the cold, so they are perfect for all of your cold-weather activities. They don’t bind and aren’t overly restricting as some performance long underwear can be. As with all Patagonia gear, they are made in ethical, sustainable ways and are very high quality and durable.

Another great place to find merino wool products is Smartwool. They have two thicknesses for their thermals, the 150 or the 250. The 250 base layer is the more popular style since it is warmer and is often used for activities that you do in the snow, like skiing or snowboarding.

They are a bit pricey, but like some of the other higher-end options, they will last for a long time, and most women find that the benefits are worth the cost. The fabric is very soft and easy to move in; it doesn’t create extra bulk or bind uncomfortably in any area. The mid-weight merino fabric has all of the benefits of merino, including regulating your body temperature as well as being breathable and odor-resistant.

Available from SmartWool.com

If you are looking for silk options, you may want to try the Lands’ End Silk thermals; these are some of the more popular silk thermals that have been around for a while. Not surprisingly, the silk styles are some of the most comfortable, but they come with a little bit of a higher price tag.

Silk is an excellent fabric for thermals because it is thin, so you can wear them under work clothes that you may wear to the office, and is an excellent insulator. The other great thing about silk is that it can wick sweat and is breathable so you won’t get too hot, giving you that extra level of comfort.

The Lands’ End Silk thermals won’t add any bulk to your look, and the silk is super soft against the skin. The tops, bottoms are sold separately, and they come in a few classic colors.

Available from Lands’ End

The Arc’teryx Rho LT Bottoms are one of the most highly regarded lightweight thermals that are designed for “lower output” winter activities, which I think means things like walking or just wearing under your clothes.

Women love this style because it does a great job of regulating your body temperature, so you don’t overheat or feel cold when wearing them, despite them being so lightweight. The material is also very breathable. They are made from something called Torrent™ fleece that has been brushed for extra softness. The fleece is also able to maintain its shape even after a lot of wear (some long johns tend to get a little sagging after a bit of use).

The other notable feature of this style is that it is an especially good fit for most women, especially if you have an athletic shape with strong muscular legs. Overall these are high quality, thin enough to wear under regular clothes, have an excellent stretch to the material, and are well-fitting for most women’s bodies.

Available from Arc’teryx.com

These LL Bean Silk Pointelle Pants are another well-known silk style that women go back to year after year. They are loved for being super-thin and very warm. The weight of the fabric is so thin that they are comfy and easy to wear under almost any type of clothes, making them an excellent option for office attire.

The L.L. Bean silk thermals are not only soft against the skin, but they are also very durable, so you can expect several years of wear if you end up purchasing this style. A lot of women love this style for travel since they don’t take up much room when packing, and you can wear them as PJs if you need to. They are also easy to hand wash and dry while traveling.

If you are interested in the silk styles, just keep in mind that they are great for wearing under regular clothes for a bit of extra warmth, but they really aren’t warm enough for prolonged outdoor activities where you are going to be in very frigid temperatures.

Available from L.L Bean

The Icebreaker Women’s Merino 200 Oasis Leggings are one of the best styles if you are looking for a seriously warm, high-performance base layer that is designed for changing conditions of winter sports activities. They are merino wool, so they will keep you warm but also wick sweat away and help regulate your body temperature if the weather gets too hot or too cold.

Available from Backcountry

If you would like a little more flair in your long underwear Sweaty Betty Ski Seamless Base Layer Leggings may be the style for you. This is another design that is super functional as a heat regulating base layer, but it also has the bonus of being fashionable and suitable enough to wear on its own.

These are a ski base layer, so they are designed to be warm. You can buy just the bottoms, but they also have matching tops to make a set. The leggings are super soft and easy to move around it. One thing to be aware of with the Sweaty Betty leggings is that they are pretty high waisted. Some women love this, but they probably aren’t the best option for you if you have a short waist.

Available from SweatyBetty.com

If you aren’t totally sold on the idea of long underwear or don’t want to add anything new to your closet, some women just wear comfy leggings under their clothes or snow pants. If you don’t have a warm pair of leggings, a comfy style that is very popular and comes in fun patterns are the Cuddl Duds Fleecewear Stretch Leggings.

Cuddl Duds do make thermals, but the more popular option is their Fleecewear Stretch Leggings. They are a little more substantial than regular leggings and are warm. Women love Cuddl Duds not only for the warmth, but they generally have an excellent fit nice around the waist and are fairly flattering for most body types.

Available from Kohl’s