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Your adventure has just begun with Smartwool's lineup of women's base layer bottoms, designed to offer unparalleled comfort, warmth, and versatility. Whether you're setting off on a snowy mountain trek, enjoying a crisp morning run, or simply seeking cozy warmth on a chilly day, our Merino wool base layers provide the perfect foundation for any outdoor activity or casual wear.
Our Classic Thermal Merino Base Layer Bottom offers the ultimate in warmth and softness for those extra cold days. For a more tailored fit and enhanced mobility, explore our Intraknit Active Base Layer Bottom, featuring innovative knit technology for dynamic movement and breathability. And for versatile year-round comfort, our Classic All-Season Merino Base Layer Bottom adapts to your body's needs, providing lightweight insulation and superior moisture management.
Find out why our collection is considered to have some of the best Merino wool base layers bottoms on the market, blending the natural benefits of Merino wool with cutting-edge technology for durability, comfort, and sustainability.
Want to shop locally? Smartwool is sold across 5,000+ stores in the U.S. Find one near you with our Store Locator tool.
Q: What temperature are these base layers best suited for?
A: Our base layer bottoms are versatile enough for all seasons. Merino 250 is ideal for colder conditions, providing extra warmth, while our All-Season and Intraknit Active base layers are perfect for milder temperatures or as part of a layered outfit for year-round use.
Q: Can I wear these base layers during high-intensity activities?
A: Absolutely! Our Intraknit Active and All-Season Merino base layers are specifically designed for a range of activities, offering breathability, moisture management, and quick-drying properties to keep you comfortable during any adventure.
Q: How do I care for my Merino wool base layers?
A: To care for Merino wool base layers, machine wash on a gentle cycle in cold water and lay flat to dry. Avoid using bleach or fabric softeners to maintain the integrity of the fibers and the performance of your garment.
Naturally versatile, renewable, and totally comfortable. Learn more about Merino wool and all the benefits that come with wearing it for all your outdoor pursuits.
We love Merino wool for its natural odor-resisting and moisture-managing abilities. Whether we’re running, biking, hiking trails, hunting, and skiing or snowboarding, Smartwool socks, base layers, and apparel help us keep us comfy and dry all day long.
We want you to be 100% satisfied and comfortable with your Smartwool purchase. Our sock, clothing, and accessories size charts are specifically designed to help you find the best fit for men’s, women’s, and kids’ Smartwool products.
Free Return Policy
Smartwool offers free returns within 30 days from the date of purchase. Items must be unused, unwashed, and unaltered.
Store Returns
Return the unworn item(s) to the store where you originally made the purchase for a refund or exchange.
Online Returns
Return unworn item(s) purchased at smartwool.com 30 days from the date of purchase for a complete refund. Initiate a return by accessing your order history and selecting “Return Items."
Refunds may take up to 3-5 weeks to process due to the time often required for shipping and bank processing. Exchanges are not available.
We are currently offering free shipping on orders $89+ placed on smartwool.com.
Shipping based on normal carrier restrictions and delays. We cannot guarantee arrival. Offer is valid for the continental US excluding Alaska, Hawaii, Puerto Rico and any US territories, as well as PO Box addresses. Delivery days are Monday-Friday, excluding US federal holidays. Free shipping may not be available for some customers.

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