Your shell gets the attention and the price tag. The layer against your skin decides whether you're warm at 3pm or shivering on the last chair, and you wear it for eight hours of climbing, sweating and cooling off.
Most base layers on the rack are polyester. It's cheap and dries fast, and it's plastic pressed against your skin while you sweat in it all day. By the second morning it smells like the first.
The Woolmark Company reports that merino can take in up to a third of its weight in moisture vapor before it feels wet, which pulls sweat off your skin. It stays warm when damp and resists odor, so you can ski a long weekend in one layer.
Natural fiber vs. synthetic base layers
Synthetic base layers dry fast and cost less, which is why they fill ski shop racks. They also trap body odor after a day, and many carry "performance" finishes for wicking or odor control that never show up on the fiber label. Merino needs no added finish to handle sweat and smell, which you can read more about in our merino wool guide.
Two things to check on any merino. Much machine-washable wool is superwash treated, a process that coats the fiber in resin. And look for non-mulesed or RWS wool if animal welfare matters to you.
Here are 15 natural fiber base layers, all merino, with no polyester in the fabric. Browse more in our merino wool collection.
For her
Tops and bottoms, from a liner-weight crew to expedition leggings.
1. Merino 200 Oasis Long Sleeve Crewe
Icebreaker
100% merino wool, 200 g/m² · $120
Icebreaker's best-selling base layer and a good first piece if you own no merino. The 200 weight keeps you warm under a shell on a bluebird day and stays thin enough for the gondola.
2. Merino 200 Oasis Thermal Leggings
Icebreaker
100% merino wool, 200 g/m² · $120
The matching bottom to the Oasis crewe, with flat seams that sit smooth under ski pants and boots.
3. Classic Thermal Merino Base Layer Crew
Smartwool
100% merino wool · from $66
Smartwool's longest-running thermal, in a dense interlock knit that holds warmth without bulk. It's marked down right now.
4. Midweight Wool Quarter Zip
Minus33
100% merino wool, 245 g/m² · $109.99
A midweight quarter zip you can vent on the chairlift and close at the top. Minus33 lists OEKO-TEX Standard 100 certification, which covers testing of the dyes and finishes.
5. Heavyweight Wool Leggings With Pockets
Minus33
100% merino wool, 400 g/m² · $119.99
Expedition weight at 400 g/m², for bitter days or anyone who runs cold. Side pockets make it an après layer too.
6. Merino Thermal Set 250
Merino.tech
100% superfine merino wool, 250 g/m² · $99.99
A midweight top and bottom for less than many brands charge for one piece. It's the cheapest way on this list to kit out a first ski trip in merino.
7. Peyton Turtleneck
Woolx
100% Australian merino wool, non-mulesed · $155
A fitted turtleneck that covers your neck without a gaiter and works at dinner after. Woolx states its merino is non-mulesed, a welfare detail to check on any wool.
8. Long Sleeve Merino Crew
Unbound Merino
100% superfine merino wool · $110
The lightest layer here, in superfine merino. Wear it as a liner under a heavier piece in deep cold, or alone on spring snow.
9. 260 ZoneKnit Thermal Leggings
Icebreaker
100% merino wool (excluding waistband), 260 g/m² · $190
The warmest Icebreaker bottom here, with vented knit zones behind the knees where ski pants trap heat. Icebreaker's 100% merino figure excludes the waistband.
For your face and neck
Two pieces for your face and neck. Both are unisex.
10. Midweight Wool Neck Gaiter
Minus33
100% merino wool, 245 g/m² · $24.99
This sits against your mouth and nose all day, where a polyester gaiter turns damp and cold from your breath. Merino takes up that moisture.
11. Midweight Wool Balaclava
Minus33
100% merino wool, 245 g/m² · $25.99
For windy lift lines and storm days. Between runs, pull it down and wear it as a neck warmer.
For him
Four men's layers, from a light zip to a true cold-day top.
12. Men's Merino 260 Tech Long Sleeve Crewe
Icebreaker
100% merino wool, 260 g/m² · $140
Icebreaker's warmer 260 weight, for men who run cold or ski in deep winter. Under a shell it handles most resort days on its own.
13. Men's Midweight Wool Bottom
Minus33
100% merino wool, 245 g/m² · $89.99
A plain midweight long john with OEKO-TEX Standard 100 certification, and the lowest-priced merino bottom on this list.
14. Men's Classic All-Season Merino Quarter Zip
Smartwool
100% merino wool · $57
A lighter all-season layer you'll keep wearing after the lifts close. Unzip it to dump heat on a bootpack.
15. Men's Heavyweight Wool Quarter Zip
Minus33
100% merino wool, 400 g/m² · $179.99
Expedition weight for backcountry days and single-digit temperatures. Layer it over a lighter crew.
What to wear under ski pants
Build from your skin out. Start with a merino base layer top and bottom, midweight for most resort days. Add a mid layer on cold days, like a heavyweight quarter zip or a wool fleece. Your shell and ski pants go on last. Skip cotton long underwear and jeans under snow pants, since cotton holds sweat and chills you once you stop moving. Finish with a merino gaiter or balaclava and a pair of ski socks with as much merino as you can find.
The short version
Upgrade the layer against your skin before your shell. Start with a midweight merino top and bottom, and add a heavyweight piece or a merino gaiter if you run cold.
Frequently asked
Merino suits most skiers. It stays warm when damp, moves moisture off your skin as vapor and resists odor, so you can wear it for several days. Synthetic layers dry faster and cost less, and they're plastic against your skin for a full day of exertion.
Weight is measured in grams per square meter. Around 150 to 200 is a light layer for spring skiing or people who run warm. 245 to 260 is the midweight most resort skiers want. 400 is expedition weight for very cold days or anyone who is always cold. When in doubt, buy a midweight top and bottom first.
Fine merino rarely itches. Thick fibers poke your skin and cause the itch, and merino fibers are far finer than regular wool. The superfine layers here are made for all-day skin contact.
The ski socks we checked use nylon for durability, from about 20 to 45 percent, and that drops them below the score bar for this list. When you shop for socks, look for the highest merino percentage. Some reach 80 percent.
Yes. Merino resists odor, so you can wear a base layer several ski days in a row and air it out overnight. Wash it cool on a wool cycle and dry it flat to keep its shape.
Some merino farmers cut skin from a sheep's hindquarters to prevent flystrike, a practice called mulesing that raises welfare concerns. Brands that avoid it say so. Look for 'non-mulesed' or Responsible Wool Standard certification.
One 2019 study found that children and adults with mild to moderate eczema had milder symptoms after six weeks in superfine merino clothing than after six weeks in their usual clothing. Wool still bothers some people with sensitive skin, so start with a superfine piece and see how your skin responds.
Often, yes. Most machine-washable wool goes through a chlorine bath and then gets a thin polymer resin coating so it won't felt in the wash, and the fiber label never mentions it. Brands rarely say which process they use, so ask them directly if it matters to you.
