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Our Kids' Classic Thermal Merino Base Layer Bottom uses our super-soft interlocking knit—perfect for layering in cool conditions and great for wearing...
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Temp Rating:
Classic Thermal
Warm
50° +
Cool
25° - 50°
Cold
<25°
Base Layer
Classic Thermal Merino
Made with 100% Merino wool for natural sweat management, odor-resistance, and temperature regulation.
Compare Base Layer Styles
Smartwool Base Layers
Responsibly sourced, naturally performing Merino wool—helping you stay dry from sweat, resistant to odors, and comfortable at the right body temperature 365 days a year.
Classic All-Season Merino
Our most versatile year-round fabric features a nylon core for durability, while keeping soft 100% Merino wool next to skin.
Classic Thermal Merino
This Base Layer
Made with 100% Merino wool for natural sweat management, odor-resistance, and temperature regulation.
Intraknit™ All-Season Merino
Our 3D-knit base layer features a fabric that combines natural benefits of Merino wool with softness and cooling properties of TENCEL™.
Intraknit™ Thermal Max Merino
Our Intraknit™ technology is helping revolutionize the base layer industry. Including 3D-mapping for a custom fit, durability, and freedom to move.
Intraknit™ Thermal Merino
Our most advanced performance base layer is 3D-knit to provide a tailored fit with mesh ventilation to balance warmth and breathability.
Features
Slim
Our slim fit is intended to follow the contours of the body
Merino wool fabric made with an interlock knit for comfort, breathability, thermoregulation, and odor resistance
Merino-lined elastic waistband designed for maximum comfort
100% Merino next to skin
Flatlock seam construction designed to help increase comfort and minimize chafing
Made in Vietnam: 100% Merino Wool. Exclusive of Decoration.
SW0SN112
Care
Machine Wash Warm Gentle Cycle.
Dry Clean.
Cool Iron As Needed
Tumble Dry Low
Do Not Bleach
The Breakdown
Comfortable in the uncomfortable.
Classic Thermal
Our fan favorite base layer made from 100% ZQ Merino wool. Ideal for cold-weather activities where warmth and breathability are crucial.
Moisture Management
Technology
Odor Resistant
Technology
Body Temp Regulation
Technology
100% Merino Wool
Fabric
Start-Stop
Activity
Cold
Temperature
Size Guide
InCm
Kids Clothing Size Chart
Size
Age
Chest
Waist
Height
Weight
XXS
3
22.5–23.5 in 57–60 cm
20–21.5 in 50–55 cm
35–41 in 89–104 cm
31–41 lbs
X-Small
4-5
24–25 in 61–63.5 cm
22–22.5 in 56–57 cm
42–48 in 106.5–122 cm
42–49 lbs
Small
6-8
25.5–26.5 in 65–67.5 cm
23–24 in 58.5–61 cm
48–54 in 122–137 cm
49–59 lbs
Medium
9-10
27–28 in 68.5–71 cm
24.5–25 in 62–63.5 cm
54–57 in 137–145 cm
59–75 lbs
Large
11-12
28.5–30 in 72.5–76 cm
25.5–26 in 65–66 cm
57–60 in 145–152.5 cm
75–89 lbs
X-Large
13-14
30.5–32 in 77.5–81 cm
26.5–28 in 67.5–71 cm
60–62 in 152.5–157.5 cm
75–89 lbs
Find the size that fits you best based on people just like you.
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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.
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Free Shipping
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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