Brands like Icebreaker
Updated November 7, 2026
Icebreaker is a New Zealand merino brand founded in 1995 and known for base layers and tees. Many of its lighter fabrics wrap merino around a nylon core or blend it with Tencel, so if you want pure merino, compare labels closely.
Look for 85% merino or more, a fiber diameter of 18.5 microns or less for softness, and a weight that fits the job: 150 to 200 GSM for active use, 250 GSM and up for real cold.
The 12 brands below sell merino wool base layers and are listed in The Plain Thread directory. The green links go straight to their matching shop pages. Some of these brands also sell blends, so check the fiber content on each product.
Merino wool base layers and cotton outdoor clothing built for hiking, climbing, and running.
Merino wool activewear and base layers for men and women at mid-market prices.
100% New Zealand merino wool base layers and travel clothing for men and women.
UK surf and outdoor brand making apparel in organic cotton, hemp, and merino.
New Zealand ZQ merino wool ski and outdoor apparel for men and women.
Merino wool outdoor and travel apparel for men and women.
100% merino wool base layers and outdoor apparel for men and women.
Merino wool socks, base layers, and outdoor apparel for men, women, and kids.
UK merino wool outdoor and casual apparel for men and women.
Merino wool outdoor apparel for men and women with a Himalayan-inspired aesthetic.
PFAS-free women's ski and outdoor apparel using natural fibers.
Outdoor brand making apparel in organic cotton, hemp, and merino wool with strong environmental advocacy.
Common questions
Why do some merino base layers contain nylon?
Nylon adds strength, so thin merino lasts longer. The tradeoff is a synthetic part that sheds microfibers. 100% merino exists but wears faster in very light fabrics.
Will merino base layers itch?
Fine merino, under about 19 microns, feels soft to most people. The itchy wool most people remember is coarser.
How warm are merino base layers?
Merino traps air and stays warm when damp. A 200 GSM layer suits cool to cold days under a jacket, and 250 GSM and up handles hard cold.