REI Co-op Merino Midweight Base Layer Bottoms - Kids'
Offering wooly warmth for cold days, the kids' REI Co-op Merino Midweight base layer bottoms are soft—not scratchy—and naturally regulate body temperature for comfort on the move.
- Ultrafine, pill-resistant 185 g/m2 merino wool offers a soft feel without the scratchiness
- Made with 100% merino wool that naturally wicks away sweat, resists odors and dries quickly
- UPF 30 sun protection
- Low-profile waistband and crotch gusset keep kids comfortable as they move
- Flat seams eliminate chafing
- Size S Kids has an inseam length of 22 in.
- Size M (10–12) Kids has a weight of 4.2 oz. (120 g)
- Machine wash warm, gentle cycle, use wool wash product, do not twist or wring, remove promptly; do not bleach; tumble dry low
- Note: not intended for sleepwear
- REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world
- Made in a Fair Trade Certified™ factory
Imported.
View all REI Co-op Kids' Base Layer Bottoms| Best Use | Multisport |
|---|---|
| Fabric | 100% merino wool |
| Sun-Protective Fabric | Yes |
| UPF Rating | 30 |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Underwear Weight | Midweight |
| Inseam (in.) | 22 inches |
| Gender | Kids' |
| Sustainability | Fair Trade Certified™ factory From a Climate Label Certified brand |
| XXS | XS | S | M | L | XL | |
|---|---|---|---|---|---|---|
| Numerical Size | 5 | 6-7 | 8 | 10 | 12 | 14 |
| Height Range | 45 | 47 1/2 - 50 | 52 | 57 | 61 1/2 | 65 1/2 |
| Across Shoulder | 11 | 12 1/4 | 13 | 13 1/2 | 14 | 14 3/4 |
| Chest | 23 | 24 - 25 | 26 - 27 | 28 - 29 1/2 | 30 1/2 - 31 1/2 | 32 - 33 |
| Sleeve Length | 21 | 22 - 23 1/2 | 24 - 25 | 26 - 27 | 27 1/2 - 28 1/2 | 29 1/4 - 30 1/4 |
| Waist | 21 1/4 | 22 - 23 | 24 - 25 | 26 - 27 | 27 1/2 - 28 1/2 | 28 3/4 - 29 3/4 |
| Hip | 23 3/4 | 24 1/4 - 26 1/4 | 27 - 28 | 29 - 31 | 32 - 33 | 34 - 35 |
| Inseam | 19 | 21 - 22 3/4 | 23 - 24 | 25 - 26 1/2 | 27 - 29 | 29 1/2 - 30 1/2 |
Sizing Notes
Measurements are stated in inches unless otherwise indicated. Size chart values represent body measurements, not garment measurements.
Inseam is measured to the floor.
Better gear is built together
From feedback to field testing, all of our gear is dialed-in by REI Co-op members. Their adventures informed every stitch and detail—making for better, longer-lasting gear.
Review this Product
Adding a review will require a valid email for verification
Most Helpful Favorable Review
Most Helpful Critical Review
Works for adults too!
I’m a woman but I couldn’t find any wool long underwear in stock in my size at REI so I checked the kids section and got lucky! For reference, I’m 5’6, 135lbs and usually wear a size 4 in jeans. I got the large and they fit similar to leggings.
Great quality
Bought shirt and pants as base layers for son to wear as we road tripped through Olympic and Mt Rainier. They kept him warm and dry through all our adventures through snow, rainforests, beaches and every where in between. We live in So Cal, so I can't attest to how it will hold up with every day wear. But we washed in gentle detergent, no softener, line dry and it was comfortable. I bought large hoping these will last into next season, but even if he outgrows these, it was well worth it to keep him safe and warm out in the elements.
Kid's pair on sale
Bought a child's size XXL in an ugly coral pink because they were on sale, and who cares how base layers look. Well, they look terrible. But they're warm and comfy so good enough for me! The only fit flaw for having gone for the child's size is that my rear end is more spacious than that of a similarly sized child, so the waistband ends up sitting too low in the back. Whatever, it's worth it for cheaper merino.
Great base
I bought these in the 4/5 for my little Florida babes first snow adventure. I was so worried that she’d be freezing and hate the snow. These base layers are such great quality and she never complained about being cold. We had these, a fleece layer, and snow jacket/pants layer. And LOVED the snow! We managed to squeeze two seasons out of them - when she was 4 1/2 & 5 1/2. Just ordered the next size up for next year! I also have a set for myself and love them.
Sizing has CHANGED drastically
I had previously purchased the same base layer and loved the shorter sizing and tighter weave of merino wool. This product has been been radically reduced by at least two inches in the waist and buttucks!!! I am SO SAD!!! Please return to the previous regular sizing of 14-16 measurements. If not, I will chose to shop else where.
Love these
very warm and comfortable for me, a 5'2 cis female
Great lightweight base layers that are not itchy
This is my second time buying for my daughter. She dislikes most merino wool baselayers because they make her feel itchy. She loves these though. They are very lightweight and fine.
Good value
Soft and warm. Fit seems true to size.
Didn't Last Long
They were good while they lasted, but the knees completely shredded out within a few months of use by my kid. Always worn under pants and not subject to abnormal abuse. We'll maybe try Smartwool next time.
Durable, Dependable, and Outgrown — not Outworn
This stuff is the absolute best. Our boys got in 100+ days skiing wearing these base layers with washing cycles to match. They outgrew the size, but the base layers are still in great shape.