Child wearing base layers

The Secret of Base Layers for Kids - Stay Warm when Out

Posted by Gav Grayston.
First Published Nov 2011; updated May 2023.

If you are hiking in the Autumn or Winter, and especially if skiing, you want to get some base layers for your kids as part of a proper layering strategy.

Just getting out in the colder months hiking or geocaching (or even winter shopping!) and base layers could mean the difference between your children being cold and unhappy to not noticing the weather. Read this guide to buying base layers for your kids.

Base layers could mean the difference between your children being cold and unhappy to not noticing the weather

Why get your kids base layers

The concept of layering clothing is now a well-recognised method for keeping warm when it's cold outside.  Each layer of clothing traps warm air and insulates the body more efficiently than just a single layer.  If you get too hot, you can remove the outer layers.

purpose designed base layers fit tighter to the body and avoid 'thermal leakage'

Thermal underwear and base layers are that first layer, and whilst a T-Shirt could be considered a base layer, purpose-designed base layers fit tighter to the body and avoid 'thermal leakage' - in other words they insulate more efficiently, with the added benefit of fitting under clothes better.

Also, unlike T-Shirts, they are not made from cotton, which loses any insulation when it gets wet - and under-clothes can get wet as bodies sweat (even if only a tiny, normally unnoticed amount).

Polar explorer Eric Larsen even recommends removing a layer or two before you do an activity so that you don't get too warm, and then putting the layers back on when you stop. If the kids are about to do some activity, it may be a good idea to take the same approach.

What is Wicking?

Damp clothes next to the skin... can make you even colder

Some base layers advertise built-in wicking of sweat.  This prevents the build-up of wet and sweaty areas, which is helpful for more strenuous outdoor activities. 

This may be less beneficial to younger children than teenagers or adults (who sweat more than kids!).  However, the wicking design helps regulate body temperature by preventing the build-up of damp clothes next to the skin, which can make you even colder.

Compression base layers are ideal for sports

Some base layers advertise 'compression'. Compression base layers are ideal for sports. Their tighter fit supports the muscles, which aids recovery and reduces the risk of injury.  Many also claim to increase performance.  The tighter fit also helps improve wicking and temperature regulation.

Unless your kids are doing any sporting activity, then compression is not high on the list of things to look for.

Merino Wool in Base Layers

You'll see many base layers advertise they are made from Merino Wool, and you can even get some base layers for kids that use Merino wool.

Merino is a type of sheep with fine soft wool and is often used in clothes for outdoor activities as it is regarded as much better than man-made equivalents.

  • It helps the body regulate temperature. It is even better when worn next to the skin, such as in base layers.
  • It absorbs water to help with wicking, but unlike many other fabrics, it retains warmth even when wet.
  • Merino wool is also slightly water resistant despite its ability to absorb water.
  • It is lightweight.
  • It naturally has some antibacterial properties.
  • It is soft and comfortable to wear - base layers from Merino wool will not feel like a scratchy old jumper 😉

What to look for when buying base layers for your kids

You can pick up a set of base layers for kids at very reasonable prices on the high street. However, we have seen a few base layers that weren't much better than a t-shirt and leggings.

There are a few things to look out for:

  • Don't buy too big and think you could get a few years out of them. If they are too big, they won't fit as tight to their skin and will not keep them as warm.
  • Merino wool base layers are often considered the best, so try and find some made from Merino wool.
  • Watch out for base layers where you must buy the top and bottoms separately. This can be good if you think your kid will need a change of top more than a change of bottoms, but watch the overall price. Base layers packaged separately can look cheaper than the sets initially but are not always in the end.
  • Base layers with a neck can keep your kids warmer since they seal in more body heat. Open-necked base layers let out more heat.
  • But if you get one with a neck (which is advisable), ensure it has a zip. If your kids get too hot, you can unzip the base layer and let out a lot of heat and remove some layers.

We bought a Kid's Engel Merino top and bottoms set from Amazon.

Engel Base Layer Review

Our little boy had no complaints about wearing them and forgot that he was even wearing an extra layer - these fit under clothes well. Despite it being really cold out, these thermals kept him warm.

You can get these either plain (a bit cheaper) or printed. We went for plain leggings but a printed top.

The plain ones looked a bit boring, but we thought they were acceptable for legs, but for the top, we wanted something that looked like a t-shirt or similar under his clothes.

When choosing the sizes with these, we felt they were just a fraction shorter than expected but still fit and being slightly shorter in the arms for the base layer is not a problem.