How to choose the best thermal underwear for winter travel
Our round up of the best thermal underwear for winter travel: adult and kids garments that will help you stay warm when sightseeing during the coldest months.
Cold weather calls for clever packing. Few things kill the joy of sightseeing quicker than cold creeping into your bones and weight restrictions on luggage means you can’t always bring with you as many thick jumpers and jackets as you would have liked.
The solution for light packing in the cold season is to invest in good thermal underwear. Non bulky, effective and versatile, thermal underwear will keep you and your kids warm and hide discreetly under your clothes so you can feel protected and pretty even during the chilliest of days.
How do I know? I am one of those people who is always, hopelessly cold and the quest for the best thermal underwear has been a constant for me for many, many years! Here is my selection of the best thermal underwear for winter travel.
Please note. I have compiled this list on the basis of my personal experience and research. Always check product specs to make sure it is suitable to the specific destination and activity you are planning. This list is intended primarily for city travel rather than intense outdoor winter sports
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This post contains affiliate links. Should you make a purchase through them, we might make a small commission.
How to choose the best thermal underwear
When looking for the best thermal underwear I look at three main characteristics: material, shape and use.

What is the best material for thermal underwear?
The best material for thermal underwear is the one that does the job for the specific activity and weather conditions you are planning for. The three below are some of the most common and popular.
Merino wool
Merino wool is often considered the best material for a thermal base layer. Made of natural material, it keeps you warm, it wicks away excessive moisture and doesn’t add too much bulk under your clothes. It is a good choice for most activities and comes in a variety of colours that makes it hugely versatile.
Pros: Natural material, versatile, it can be worn without washing for more than one day day.
Cons: Often expensive, very sensitive skins may find it a little rough
Silk
Silk is another popular thermal base layer thanks to its moisture absorbing property and ability to retain heath. Like merino wool it is a natural material and while not quite as warm, it is a good solution for medium-cold climates.
Pros: Natural material, super soft on the skin, not bulky
Cons: Expensive, requires frequent washing
Synthetic fabrics
Many thermal underwear options on the market are made of synthetic fabrics, usually mixing varying percentages of polyester with other materials such as nylon, ryon etc.
Synthetic fabrics have the advantage of being cheap and very easy to care for but do have some downside, mostly the fact that they tend to build odour quickly and therefore need frequent washing.
Pros: Cheap, easy to care for
Cons: Build odour quickly, need frequent washing
Whatever type of material you choose for your thermal underwear, make sure that the material is able to absorb and retain moisture.
When moving in cold conditions, even just if sightseeing, moisture may build up and if your under layer doesn’t absorb it, you will end yup feeling very cold.
Look for brands that offer moisture wicking properties to make sure you can perspire but moisture stays away from your skin and your core body temperature stays stable.
Thermal underwear shapes
Thermal underwear comes in several shapes: long and short sleeves, more or less fitted, with round neck or high neck.
The best shape for thermal underwear is one that hugs your body without making you feel constrained: a baggy thermal layer will not be able to retain much heat and will basically defeat its purpose.
In terms of neck, it depends largely on the use you may need to make of the layer.
If you want to hide it under everyday clothes a round neck is best but for thermal insulation purposes I find high neck is fundamental. Choose one with a zip so you can let air out should you need to. I find a high zipped neck exceptionally useful with kids since they tend run more and can easily get too hot.
Use
The choice of the best thermal underwear depends also largely on the use you need it for.
If you are out on a sports adventure, the moisture absorbing qualities of the item are crucial while if you need an extra layer for winter city travel you are likely to be able to get away with a less high tech solutions.
Silk: perfect if, like me, you are one of those people who are just cold all the time. Pleasant to the touch and non bulky, you can wear silk under anything and it will keep you warm all day: you can even wear it under skinny jeans, it is that thin!
Merino wool: perfect if you plan physical activities during the day or if you will be in and out frequently.
Merino wool absorbs moisture and keeps you warm but will not make you overheat indoors. For city travel and sightseeing, go for a lightweight option.
If you are planning a real winter adventure with snow and outdoor pursuits, heavy weight merino wool is my choice. Its excellent moisture wicking abilities will keep you warm all day and you don’t’ need to worry bout overheating when you stop
Synthetics: Syntetics can feel really smooth on the skin and I find them good especially for the children who tend to move and run arond more than us. My kids in particular like how the material feels on the skin and because of their small size I can pack a few of them easily and put them in the wash on our return.
Best thermal underwear 2020/2021 roundup
These are our top picks for thermal underwear for 2020/2021 and some of the best brands for thermal wear for winter, based on our travels.
| Thermal underwear brand | Who is it for | Thermal items | Materials available |
| Helly Hansen | Women, Men, Kids | Tops/bottoms | Merino Wool, Polypropylene, polyester |
| Terramar | Women, Men, Kids | Tops/Bottoms | Silk, Wool, Polyester |
| Cuddle Duds | Women, Men , Kids | Tops/bottoms | Polyester, Nylon, Spandex |
| Minus33 | Women, Men | Tops/Bottoms | Merino Wool |
| Icebreaker | Men, Women, Kids | Tops/Bottoms | Merino Wool |
| DuoFold | Women, Men | Tops/Bottoms | Polyester, Spandex |
If you are interested in more winter packing tips for travel, you may enjoy our packing list for visiting Amsterdam in winter and our Iceland in winter packing list with all our essentials.
Best women’s thermal underwear 2020/2021 winter
This my favorite thermal wear for women
Helly Hansen Women’s HH Active Flow Long Sleeve Base Layer Shirt
Terramar Thermasilk Tall Crew Neck Top
Smartwool Merino 150 Base Layer Pattern Long Sleeve
Cuddl Duds Women’s Flexfit Long Sleeve Crew Neck Top,
Best men thermal underwear for winter 2020/2021
This is thermal wear for men we like
Smartwool Men’s Merino 150 Base Layer Long Sleeve
Cuddl Duds ClimateSport Long Sleeve Crew
Helly Hansen Men’s HH active flow
Terramar Thermasilk Crew
Icebreaker Men’s BodyfitZone Zone Leggings
Best thermal underwear for kids
This is the thermal wear for kids we use
I hope this round up of what we find the best thermal underwear for winter travel was useful. As always, please remain advised that this article is based on our own experience and only reflects our opinion on the products.
This post was originally published in 2018 and has now been updated with our pics for winter 2020/2021.


