9 Best Base Layers for Kids: Merino Wool and Synthetic to Stay Warm This Winter

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If there’s one thing that I hate more than actually being cold, it’s having COLD KIDS. Not only because I feel so bad for my cold kids, but also because they complain, whine, and cry to no end when they’re cold.

However, after over a decade FULL of winter adventures with our kids, I’ve learned that the secret to keeping kids warm in winter starts at the bottom, with GOOD KIDS BASE LAYERS.

Truthfully, base layers for kids are some of the most neglected pieces of kids winter gear (though we use them year-round, especially for kids camping and hiking trips). It’s easy to remember that kids need a coat, snow pants and snow boots, but it’s easy to forget to invest in the best base layers for kids and a good pair of wool socks as well.

Layering Kids Clothing in Winter

If you’re new to dressing kids for outdoor adventures in winter, you need to know that the best way to keep kids warm in winter is with layers. There are three major layers that you need to consider when dressing your kids in winter.

Base Layers for Kids

This layer is exactly what it sounds like – the bottom layer that you wear. Your kids base layers directly touch their skin, so make sure that they are the most comfortable winter layer for kids and also that they fit well. Kids base layers should be snug but not super tight. The goal of a good base layer for kids is to wick sweat away from their body and to also insulate them against the cold. We have found that the best base layers for kids are made of merino wool or synthetic material since they can both wick and insulate at the same time.

Remember that a base layer is not meant to be your kids only winter layer. In fact, since base layers are designed to wick, your child will be significantly warmer with another layer on top, since that’s how base layers for kids are designed to work.

Read: Best Kids Ski Socks

Mid Layers for Kids

A kids mid layer in winter is worn on top of the base layer. This is worn to keep kids extra warm, and our favorite mid layers for kids are fleece shirts or lightweight fleece jackets. These are easily found and can be a very affordable way to keep kids warm while skiing and keep kids warm in the snow. On extra cold days, we layer our kids with a puffy jacket.

Read: Best Kids Mid-Layers

Outer Layers for Kids

A kids outerwear layer is designed to keep the elements OFF! This includes water, wind and snow. The best kids outerwear is both windproof and waterproof. This includes hats, waterproof ski coats for kids, waterproof snow pants for kids and snow boots.

A Note About Base Layers in 2023-24

This season we’re already seeing unprecedented demand for kids base layers. Most top brands are almost sold out. For the best inventory, shop for merino wool at Iksplor (code bringthekids for 20% off) and synthetic base layers at Shred Dog (code SKIINGKIDS for 20% off)! If you’re looking for kids base layers, BUY FAST! Also, all of the brands that we mention below are GREAT, so if you don’t find one that suits you, look at another brand. Here are our top recommended picks (more detailed reviews below).

Kids Wool Base Layers, Quick Picks:

Iksplor: Lightweight and soft – best availability of sizes for wool base layers as of January.

Chasing Windmills: Super durable and soft – low base layer supply, but their merino wool mid layers are incredible! Check out their merino mid layers HERE!

Reima Taitoa: Bamboo lined for super soft feel – STILL AVAILABLE IN BIG KID SIZES!
Reima Kinsei: Basic and Affordable – STILL AVAILABLE IN BIG KID SIZES!

Kids Synthetic Base Layers, Quick Picks:

Shred Dog: Thicker, super warm, brushed lining for softness – LOTS OF SIZE AVAILABILITY

Reima Lani: Great for layering, good wicking – Big Kid Sizes Still Available!!
Rocky Thermals: Warm, inexpensive

Base Layer Discount Codes:
Ikslpor 20% off with code bringthekids
Reima 15% off with code BRINGKIDS15
Shred Dog 20% off with code SKIINGKIDS

Check Out Our Kids Outerwear Reviews:
Best Kids Snow Pants
Best Kids Gloves

Girl Base Layers vs Boy Base Layers

I often get asked if there is a difference between base layers for boys and base layers for girls, and it really depends on the brand. If a brand advertises something as thermals for boys or thermals for girls (base layers are often called thermals), stick to the gender if you can. Base layers for girls often have a shiny trim or a ruffle around the edges and base layers for boys usually have a fly on the outside, just like boys’ underwear do. Trust me, you don’t want to embarrass your boy by having him wear ruffled sleeve base layers and most girls would be mortified to be seen in a base layer with a fly.

Thankfully, most of our favorite base layers for kids are gender-neutral so they work for both boys and girls.

Base Layers for Skiing and Snowboarding

If you want your kids to last longer and stay warmer and drier while skiing and snowboarding, a good pair of base layers is one of the best investments that you can make. We are incredibly particular about our kids ski base layers, because we know they work up a sweat AND get super cold on the chairlift. The base layers below all have our stamp of approval for being great base layers for skiing!

Best Merino Wool Base Layers For Kids

Merino wool is ideal for active kids because it regulates body temperature, absorbs odors more readily due to its antibacterial properties, and wicks moisture from sweat that would otherwise keep kids too cold. We recommend merino wool as the best base layer for boys, since they tend to sweat and stink more than girls, and merino naturally repels odors!

Parents often avoid merino wool for kids because merino wool is often a more “high maintenance” fabric with special wash instructions. Can I let you in on a little secret? I always wash ours in the washing machine on cold and throw them in the dryer with the rest of the clothes (medium-low temp), and I’ve never had a problem with them shrinking or getting ruined (obviously, this may just be my experience so use your own judgment).

Our kids love merino wool so much that we use it year round and always pack it when we travel (merino wool does a great job of cooling in warm temperatures!). Our kids wear it as pajamas even in the summer and we pack it along on hikes where there’s a chance that we’ll get chilly or run into bad weather. Most people consider merino wool the best base layer kids can wear!

Note: merino wool can be a more expensive material for winter base layers for kids, but the quality of the material is AMAZING! Our favorite children’s base layers below feature one with a discount for our readers and another with a lower starting price!

Chasing Windmill Kids Base Layer Review: Best Prices

Pros: Reinforced knees (ultra durable), warmer Mid-weight wool, low direct to consumer pricing

This is one of the absolute best kids base layers from merino wool. We have used these nonstop for YEARS and they are still going strong. We love that Chasing Windmills is a family run company based out of Colorado that is really invested in making it easier for kids and families to get outside.

These kids merino wool layers have a good snug fit and the stretch is also fantastic. They work well for my slim kids, but also stretch enough that we were able to fit them for several years (we finally had to say goodbye to a pair of 2T toddler base layers after my son wore them for 3 years…he’s 4.5 and could still squeeze into them). My son literally wore these as a toddler base layer (they go up to size 12) and had them on at least 2-3 days a week in the winter (for skiing, sledding, etc), and wore then at least 2-3 nights a week YEAR ROUND as pajamas. All of this for 3 years and it wasn’t until the last month that we got any holes in them. They are SO GOOD!!

My absolute favorite thing about these gender neutral base layers for kids is that they have reinforced knees so they last extra long (this is always where my kids get holes first, so this really extends the wear time). We have used and abused these for years and absolutely adore them.

We love that this company offers direct to consumer pricing keeping costs low for everyone, so you don’t even need a discount coupon to save big here. A set of their thermal long johns will cost you about 30% less than most other brands.

Chasing Windmills Merino Wool Thermals for children

• Lower cost than most brands (about 30% less than the average kids merino sets)
• Reinforced knees so they’re super durable
• Super stretchy to help them last longer
• Fits well under clothing
• Gender neutral

Iksplor Merino Wool Kids Base Layers review + DISCOUNT CODE

Pros: Lightweight, great for sensitive skin, discount available

We have 2 brands of merino wool base layers for kids that we absolutely LOVE and Iksplor is one of the all time best kids base layer brands. Our kids have been wearing these for a couple of years and we absolutely love them.

The best thing about Iksplor merino wool layers for kids is that they are SO SOFT! One of our boys is very sensitive to different fabrics, so base layers for him have always been a challenge. Not only does he love these boys base layers, but he went through a phase where he would literally wear them 3-4 days a week since they were so much more comfortable than all of his other clothes (thank goodness we homeschool!). He walked around for an entire winter dressed in his Iksplor layers and was constantly telling people these were the best thermals for kids.

Iksplor Merino Wool Thermals:

• Super soft
• Huge color variety
• Available in size 2- 12 (with baby merino wool base layers too)
• Generously long thermals for kids
• Machine washable and dryable (on low)
• Gender neutral

Reima Taitoa Merino Wool/Bamboo Blend Kids Base Layer

Pros: Crazy soft, warm

Use code BRINGKIDS15 for 15% off at Reima

Reima really knocked it out of the park with this wool and bamboo base layer for kids. It’s honestly so incredibly soft that my daughter wears them almost daily. The soft bamboo is directly next to kids skin to give it a super smooth feel and help absorb moisture. The wool on the outside keeps kids warm and regulates their temperature whether they’re hot and sweaty from running around or just sitting around in the cold. If you want super soft kids base layers, we highly recommend the Reima Taitoa. They’re also perfect for kids who don’t love the feel of merino wool on their skin, since the bamboo layer is what touches them!

Reima Kinsei Merino Wool Kids Thermals

Use code BRINGKIDS15 for 15% off at Reima

These kids wool thermals are worn on repeat at our house. They’re pretty basic merino wool, that are really stretchy so they seem to grow as your kids do! Our oldest hit a major growth spurt just after getting these, so I’m really thankful for how stretchy they are. These are fantastic kids thermals for really ative kids and we love how well the wool helps to regulate kids temperature, whether they’re hot and sweaty or chilly! These go up to a size 14, so they’re great thermals for teens!

Icebreaker Kids Merino Wool Review

We’ve been wearing Icebreaker kids base layers for close to 10 years with our kids. These are your best option if you need just a base layer top or base layer bottom since they can be sold separately. They are also a great option if your kids need a different top and bottom thermal size. Icebreaker is sold by a lot of online retailers, so you can sometimes find a great sale on them, making them the most affordable merino wool base layers for kids. Some Icebreaker base layers are gender neutral and others are not, so check styling closely!

Synthetic Base Layers For Kids

There are lots of great options for synthetic base layers for kids that are fantastic quality. Base layers that are synthetic are often made of polyester or polypropylene with other synthetic fibers woven in as well. The biggest downside of synthetic base layers is that they tend to hold onto odors more, so you have to always wash them thoroughly. The good news is that synthetic base layers are usually the cheapest kids base layers.

Shred Dog Base Layer Review + DISCOUNT CODE

Shred Dog makes some of the best affordable base layers for kids, made even more affordable with our discount code below! Shred Dog specializes in ski and snowboard clothing for kids, and we consider these to be some of the best ski base layers for kids.

Shred Dog base layers are thicker than most others that we included in our kids base layer review, but they have excellent quality. The top is a 1/4 zip top that’s a little more bulky than most, but that also means that it works well to be worn alone. The base layer bottoms for kids are great and super warm. The styling of these thermal bottoms have a great fit, so my daughter actually prefers to wear these as pants instead of leggings, since they’re so much warmer than any other pants that she has. Overall, these are the warmest kids base layers for winter and work great on their own, even without other layers on top.

These are also the softest kids thermals since both the top and the bottom have brushed fabric making them feel almost like a cozy fleece backing.

If you are looking for a more stretchy base layer top, grab the Shred Dog advanced seamless baselayer top. It’s got tons of stretch, and I love that there is a gusset behind the 1/4 zip so that girls can still stay modest even while getting ventilation!

Reima Lani Best Kids Thermals

Use code BRINGKIDS15 for 15% off at Reima

If you’re looking for a really great pair of kids thermals, the Reima Lani is a great basic option. These kids thermals do a great job of wicking moisture away from the skin and helping to keep kids warm. This is a lightweight thermal set that’s great for layering under other clothes, and they’re perfect under a good kids mid layer. This is a great pair of kids thermals for teens up to size 14.

Rocky Thermals Base Layer Review

I’ve seen the Rocky Thermals base layers popping up on Amazon for quite a while now, and we finally got a pair to see what the hype was all about. Our first impressions are really great and these are hands down the cheapest kids base layers for the quality they provide.

Overall these are thicker base layers for kids than most others that we have found. While you could wear the top underneath other clothes, the bottoms may not fit well under other pants. They do seem incredibly warm though, so if you need warm kids base layers, these may be a great option.

We’ve only been wearing them a bit, but many of the reviews mentioned problems with pilling, so we’ll be keeping a watch out for that as we wash them more and more (so check back for updates!). If you need affordable base layers for kids, Rocky Thermals is a great budget base layer option.

NOTE: Rocky Thermals are GENDER SPECIFIC!

LL Bean Wicked Warm Expedition Weight Long Underwear

We really love the kids base layers from LL Bean, and if you want warm thermals for kids, this is an amazing high quality option. Our kids have been wearing these for 3 years and they honestly still look brand new, with no holes, running or other problems – the quality is outstanding. Similar to other brands, these warm long underwear for kids have a brushed lining, making them extra soft and cozy, so kids will want to wear them regularly.

There are 2 different styles of tops for these LL Bean base layers, and hands down, the kids base layer with a hood is our favorite. Not only does it have a snug fitting hood (that’s thin enough to wear under a helmet), but it also has a face mask that you can pull up, making this the perfect pair of long underwear for really cold days. We also love that these are incredibly affordable childrens base layers, with pieces starting at just $25/piece.

Best Baselayers for Babies

Iksplor Baby Set

Iksplor makes some of the softest 100% merino wool baselayers and the Iksplor Baby Set is no different. The Baby Set is so soft and smooth against my baby’s sensitive skin. The merino wool doesn’t cause any chafing or irritation in any of my kids. 

The best part about Iksplor’s Baby Set is that it is machine washable. Since they are antibacterial they don’t need to be washed very often. When I do want to wash them I get all of our Iksplor sets and wash them on cold and then hang them dry or dry on low. 

The Baby Set is an essential part of our baby’s wardrobe. We use it all the time and it is the perfect 100% merino wool base layer. It is the perfect base layer to layer with the Iksplor Baby Adventure Zippy. Choosing high-quality merino wool can make such a difference when going on adventures with kids.