REI Co-op Midweight MTS Long Underwear Bottoms - Kids'
This product is not available. Good news: we have a newer version.
Soft and comfortable, the MTS midweight long underwear bottoms from REI are lightly brushed on the inside with a spun polyester on the outside for an excellent warmth-to-weight ratio.
Shop newer version- MTS® (Moisture Transport System) fabric wicks away moisture and dries quickly
- Lycra® spandex helps garment stretch
- Fabric provides UPF 50+ protection from harmful solar rays
- Flat seams eliminate bulk; rib-knit ankle cuffs help seal out cold
- 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
Imported.
View all REI Co-op Kids' Base Layer Bottoms| Best Use | Multisport |
|---|---|
| Fabric | 94% polyester/6% Lycra spandex |
| Sun-Protective Fabric | Yes |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Underwear Weight | Midweight |
| Inseam (in.) | 25 inches |
| Gender | Kids' |
| Sustainability | 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.
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LOVE THEM!!!
I am 23 years old and 5'10 and these pants fit me perfectly! Marketed towards children but I got the XL and they are WAY longer than the women's version and the waist is perfect too. The price is the best part. I bought these along with the matching top which I also love and they cost me 1/3 of what I would have paid for the "grown-up" version and they work just as well! I wear them under my pants and shirts for work, where I am a field technician and outside for 10 hours a day in variable weather conditions. I highly recommend these, they keep me warm even in freezing temps!
Must have if you want to keep warm!
At 120 lbs, 4'11" (and reading the other reviews)went with the recommedation and purchased XL top and bottom. The shirt and pants were too long and exchanged the set at an REI store. To my surprise the "S" was the perfect fit and bought 2 more other sets. The new size fits snug (as I wanted) and the shirt's length, sleeves and pants were all perfect! I use them under dress pants and sweater and I'm comfortable throughout the day. This will be part of my layering on my coming trip to Alaska!
good deal
I loved these until i made the mistake of sleeping in them. They have heavy pilling on the outside. The inside is still soft and nice though. I like the fact that they don't get saggy. Im am 4'11 so I bought the kids XL. They fit great and I'm not a skinny petite woman. They make my rump look nice. I am going to buy more of these since they are on sale right now but not sleep in them.
Nice multi-use pants
My son uses these to run in, hike in, sleep in, and backpack in. They are warm, but not to warm, and because of the design, they function just as well as running tights in cool weather as they do as sleepwear on the Appalachian Trail. Bottom line is...he likes them a lot and wears them constantly. Another really nice REI only item.
excellent product
I purchase a pair of these thermals for my daughter each year. She wears them during the winter months at school and never overheats out on the playground. Both the top and bottoms are non-binding and comfortable beneath clothing. This is her base layer for skiing and is warm all season. Great price. Great product.
Great for scouts
The best long underwear my son has found. He lives in these. He says they are as comfy as his PJs. They are great for hiking in the NW. Worn with zip off pants they have a great temperature range, and dry super fast.
Year Round Wear
My son has worn these as summer pajamas and under winter clothes for several years. The only shortcoming is that the knees develop holes easily. If the knees were reinforced with a double layer, they'd be perfect!
dries fast
While driving up to go sledding, my daughter spilled water on these. I was dismayed, but we were able to dry them out holding them in front of the car heater vent for 5 minutes. She was very happy.