Kids' Classic Thermal Merino Base Layer Bottom
Pickup available at Arlington, TX
Usually ready in 24 hours
Shipping Policy
×Free standard ground shipping on most orders over $150
| Order Amount | Standard Ground | Air Shipping |
| US Dollars | 1 - 10 Business Days | 1 - 3 Business Days |
| 0-$149.99 | $7.95 | cost |
| Over $150 | Free | cost |
Alaska & Hawaii Shipping
-
Actual shipping charges apply; ground service isn’t available.
-
Choose UPS 2nd Day Air if you want expedited delivery.
Air Shipping Options
-
Next Day, 2nd Day Air, and 3 Day Select are available at actual cost.
-
Shipping costs are shown on each product page under “View shipping cost.”
-
Some items can’t ship by air.
Processing & Transit Times
-
Shipping times are business days only (no weekends or UPS holidays).
-
Orders are shipped Monday–Friday only. Orders placed after our daily cutoff, on Friday, or over the weekend will ship the next business day (typically Monday unless it is a holiday). Expedited services (e.g., UPS Next Day Air) ship and deliver on business days only unless otherwise noted
-
Orders placed by noon CST often ship the same day; otherwise, most ship the next business day. Orders placed after noon CST on Friday will ship the next business day, typically Monday unless it is a holiday
-
Weather or carrier delays may affect delivery.
- Most orders ship via UPS. We cannot deliver to P.O. Boxes.
Extra Charges
-
Oversized or heavy items may incur additional shipping charges. If this applies to your order, we will contact you before processing the shipment.
-
For orders containing multiple items, actual shipping charges may sometimes be lower than the quoted amount due to combined packaging
Free Shipping
-
Free shipping applies only to items available for purchase on our website and excludes kayaks
-
Free shipping promotions apply to standard ground shipping only and are limited to orders shipping within the continental United States.
UPS Transit Reference
-
Estimated UPS delivery times can be calculated using the UPS website
-
Our shipping origin ZIP code is 76013.
Return Policy
Return Window
You have 30 days from the day your order is delivered to start a return or exchange.
For more information on returns, exchanges, and the full policy, visit our Refunds & Exchanges Page.
Return Policy
×Our Promise
At Mountain Sports, we want you to love your new items. If something isn't right, we make it easy (and free!) to return or exchange your purchase within the guidelines below.
Return Eligibility and Timeframe
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Returns and exchanges are free for 30 days from the day you receive your order, with the exception of oversized items (see below).
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You can choose a refund to your original payment method, an exchange, or store credit.
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Items must be unused and in original condition, including all tags, packaging, and accessories.
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Please do not use the shoe box or product packaging as the shipping box. Please place it inside a separate shipping carton.
Items That Cannot Be Refunded (Unless Defective)
For everyone's safety and due to industry standards, the following items are not refundable unless they arrive defective:
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Climbing gear (harnesses, carabiners, ropes, etc.)
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Food items
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Water filters
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Cut cord/rope
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Special order items
If you believe one of these items is defective, contact us so we can review your situation and make it right.
Oversized Items — $40 Flat Return Shipping Fee
Some bulky products (large tents, certain hard goods, oversized equipment, and similar) ship via oversized carriers and are flagged as Oversized Item on the product page before you complete your order. The flat $40 return shipping fee that applies to these items is disclosed at the time of ordering, so you'll know upfront if your item qualifies.
If you later choose to return the item, the $40 return shipping fee will be deducted from your refund or store credit when your return is processed. The returns portal will surface this fee for you again when you start the return, so there are no surprises.
If your oversized item arrived damaged, defective, or as a result of our error, the $40 fee is waived and return shipping is on us. If you're unsure whether your item qualifies as oversized, or you have questions before placing an order or starting a return, please reach out — we'd rather talk it through with you first so you aren’t caught off guard!
How to Start a Return or Exchange
The fastest way to start a return or exchange is right in our returns portal. Enter your order number and zip code, choose the item(s) you'd like to return or exchange, tell us why, and we'll generate a prepaid shipping label for you on the spot.
[Start your return or exchange →]
Prefer to talk to someone? You can also email us at hospitality@mountainsports.com or call (817) 823-0010 and we'll walk you through it.
Shipping Your Return
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Standard returns and exchanges include a free prepaid shipping label, generated automatically when you start your return in the portal.
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Oversized items include a prepaid label as well, but the $40 flat oversized return shipping fee (disclosed at the time of ordering) will be deducted from your refund or store credit.
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Pack your item securely with all tags, accessories, and original packaging included.
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Drop the package at the instructed drop off location.
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If your return is due to our error or a defective item, shipping is always on us — no exceptions, including no oversized-item fees.
Where to Send Your Return
The prepaid label generated in the returns portal includes the correct shipping address. If you need it for any reason, returns ship to:
Mountain Sports 2025 W. Pioneer Pkwy. Arlington, TX 76013
Refunds and Original Payment Methods
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Refunds are issued to your original form of payment unless store credit or exchange are selected.
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For oversized items, the $40 flat return shipping fee is deducted from your refund, store credit, or exchange balance.
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Once we receive and inspect your return, your refund, exchange, or store credit will be processed as quickly as possible.
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You'll get an email confirmation when your refund or exchange has been processed.
Exchanges
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Exchanges are easy in the returns portal — pick the size, color, or alternate item you'd like and we'll get it on its way.
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If you're unsure what to exchange for, give us a call at (817) 823-0010 and we'll talk through options that fit your needs.
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Customers near our Dallas-Fort Worth store are welcome to bring items in for an in-person exchange.
Questions or Need Help?
Our team is here to make your experience as smooth as possible. If you have questions about fit, sizing, oversized status, returns, or exchanges, please reach out before you ship your item back so we can help you choose the best option — call us at (817) 823-0010 or email hospitality@mountainsports.com. We'd genuinely rather hear from you up front than have you guess.
Shipping Policy
×Free standard ground shipping on most orders over $150
| Order Amount | Standard Ground | Air Shipping |
| US Dollars | 1 - 10 Business Days | 1 - 3 Business Days |
| 0-$149.99 | $7.95 | cost |
| Over $150 | Free | cost |
Alaska & Hawaii Shipping
-
Actual shipping charges apply; ground service isn’t available.
-
Choose UPS 2nd Day Air if you want expedited delivery.
Air Shipping Options
-
Next Day, 2nd Day Air, and 3 Day Select are available at actual cost.
-
Shipping costs are shown on each product page under “View shipping cost.”
-
Some items can’t ship by air.
Processing & Transit Times
-
Shipping times are business days only (no weekends or UPS holidays).
-
Orders are shipped Monday–Friday only. Orders placed after our daily cutoff, on Friday, or over the weekend will ship the next business day (typically Monday unless it is a holiday). Expedited services (e.g., UPS Next Day Air) ship and deliver on business days only unless otherwise noted
-
Orders placed by noon CST often ship the same day; otherwise, most ship the next business day. Orders placed after noon CST on Friday will ship the next business day, typically Monday unless it is a holiday
-
Weather or carrier delays may affect delivery.
- Most orders ship via UPS. We cannot deliver to P.O. Boxes.
Extra Charges
-
Oversized or heavy items may incur additional shipping charges. If this applies to your order, we will contact you before processing the shipment.
-
For orders containing multiple items, actual shipping charges may sometimes be lower than the quoted amount due to combined packaging
Free Shipping
-
Free shipping applies only to items available for purchase on our website and excludes kayaks
-
Free shipping promotions apply to standard ground shipping only and are limited to orders shipping within the continental United States.
UPS Transit Reference
-
Estimated UPS delivery times can be calculated using the UPS website
-
Our shipping origin ZIP code is 76013.
Return Policy
Return Window
You have 30 days from the day your order is delivered to start a return or exchange.
For more information on returns, exchanges, and the full policy, visit our Refunds & Exchanges Page.
Our Kids' Classic Thermal Merino Base Layer Bottom uses our super-soft interlocking knit, perfect for layering in cool conditions and great for wearing alone on a mild day. Now your kids can be as warm, dry, and comfortable as you are.
Features
Materials & Care
Specs
About The Brand
Smartwool Size Chart - Kids' Apparel
Smartwool Sizing Chart
Measurements are in inches, unless otherwise noted. Charts reflect body measurements, not garment measurements.
Kids' Apparel & Base Layers:
| Size | Age | Chest | Waist | Height | Weight (lbs) |
|---|---|---|---|---|---|
| XXS | 2 - 3 | 22.5 - 23.5 | 20 - 21.5 | 35 - 41 | 31 - 41 |
| XS | 4 - 5 | 24 - 25 | 22 - 22.5 | 42 - 48 | 42 - 49 |
| S | 6 - 8 | 25.5 - 26.5 | 23 - 24 | 48 - 54 | 49 - 59 |
| M | 9 - 10 | 27 - 28 | 24.5 - 25 | 54 - 57 | 59 - 75 |
| L | 11 - 12 | 28.5 - 30 | 25.5 - 26 | 57 - 60 | 75 - 89 |
| XL | 13 - 14 | 30.5 - 32 | 26.5 - 28 | 60 - 62 | 89 - 100 |
How to measure - Chest: measure under the arms, around the fullest part of the chest and back. Waist: measure around the natural waistline, keeping the tape a bit loose. Height: measure standing straight, without shoes, from the top of the head to the floor.
Smartwool clothing runs true to size. If your child is between sizes, age, height and weight are good guides for choosing the best fit. Smartwool products are designed to retain their fit and shape; following the care instructions on the label will help avoid shrinking or stretching.
