When it comes to layering for the outdoors, your base layer does all the heavy lifting. It’s the first thing against your skin, keeping you warm, dry, and comfortable. But most conventional base layers are made from polyester or nylon, which shed microplastics and rely on fossil fuels.
I’ve discovered a few brands that are making base layers from natural fibers and recycled materials so we can all stay cozy without the environmental baggage.
Here are some great brands making sustainable base layers worth checking out:
1. Icebreaker
One of the best-known merino brands, Icebreaker makes base layers in a range of coziness, from the lighter 200 Oasis LS Crew to the warmer 260 Tech LS Crew. All their merino is mulesing-free, and they’ve been pioneers in transparent supply chains and natural alternatives to synthetics.
Price range: $95–$150
🌍 Ships worldwide, and available through select retailers in the US, EU, and beyond.
2. Smartwool
Smartwool’s Merino 250 crew and their All-Season zip tops are staples in many outdoor wardrobes. The brand focuses on responsibly sourced merino and durability, so you can wear each piece for years. Their layers are cozy, breathable, and made for everything from casual hikes to alpine climbs.
Price range: $85–$140
🌍 Ships from the US, with global retailers carrying their products.
3. Mons Royale
This New Zealand brand brings a modern, stylish twist to merino. Products like the Cascade LS and Yotei LS are performance-oriented but look good enough to wear off the slopes too. They prioritize mulesing-free merino and sustainable farming practices, making them a solid eco-friendly choice.
Price range: $100–$160
🌍 Ships internationally, with retailers in Europe, the US, and New Zealand.
4. Kari Traa
This Norwegian brand is popular among skiers and hikers for good reason. Their merino wool base layers are soft, moisture-wicking, and naturally odor-resistant. Kari Traa uses IWTO-certified wool and avoids harmful PFAS chemicals in their water-repellent treatments. While they still use some synthetics, they’re steadily increasing recycled content.
Price range: $80–$140
🌍 Ships from Norway and the EU, with international shipping available.
5. Odlo
Odlo’s Merino 200 line blends merino with recycled fibers for warmth, breathability, and stretch. They’re one of the few big performance brands really investing in sustainable materials. Odlo also has a fully recycled Active Warm Eco collection for cold-weather sports.
Price range: $70–$130
🌍 Based in Switzerland, with shipping across Europe and global availability through outdoor retailers.
Made with kids in mind, Isbjörn uses mulesing-free merino blended with bamboo for extra softness. Their Husky base layers are durable, cozy, and designed for active little adventurers, a thoughtful choice if you’re raising outdoorsy kids sustainably.
Price range: $60–$120
🌍 Ships mainly within Europe, with some international availability.
7. Dilling
Dilling is a Danish family-owned brand that’s been creating simple, functional merino base layers since 1916, with a big focus on slow production and clean processing. Their wool is always mulesing-free, and they use a certified Nordic Swan eco-friendly dyehouse with no chlorine or harsh chemicals. They focus on timeless basics rather than sporty graphics, which is perfect if you prefer a more minimalist vibe.
Price range: $60–$120
🌍 Ships across Europe and the US, with worldwide shipping available.
8. Paka
Instead of merino, Paka uses ethically sourced alpaca fiber blended with TENCEL™ for an ultra-soft, lightweight, and surprisingly warm base layer. Their alpaca comes from small-scale Andean herders in Peru, and every piece is traceable down to the exact region it was sourced from. The fabric is naturally breathable and odor-resistant, and they package and ship everything plastic-free. It’s a great alternative if you’re looking for something natural but not wool-based.
Price range: $95–$160
🌍 Ships from the US and Peru, with carbon-neutral international delivery available.
Also working with Peruvian alpaca, Arms of Andes makes minimalist, performance-ready base layers using single-origin alpaca wool that’s naturally temperature-regulating and antimicrobial. They avoid synthetic blends entirely, sticking to one natural fiber per garment, and use low-impact dyes to keep things as pure as possible. Their clothing is especially good for travelers and hikers who want warmth without bulk or odor buildup.
Price range: $100–$170
🌍 Ships internationally from Peru, with delivery options across the US, EU, and beyond.
Base layers might seem like a small thing, but they’re the one article of clothing you wear on every trip. Choosing natural, responsibly made products reduces plastic pollution, supports better farming practices, and usually means you get something that lasts longer. And when you only need one or two great base layers instead of a drawer full of synthetics, it’s obviously better for both your budget and the planet.