REI Co-op Midweight Base Layer Bottoms - Kids'
A thermal base layer that wicks for warmth, the kids' REI Co-op Midweight base layer bottoms help keep them comfortable for all-day exploring and adventuring in colder weather.
- Durable recycled polyester/spandex blend fabric is soft and sweat-wicking
- 257 g/m2 fabric weight offers midweight warmth
- UPF 50+ sun protection
- Low-profile waistband keeps kids comfortable as they move
- Designed to hug the body for optimum performance
- Soft, durable flatlock seams are smooth and comfortable
- Size S Kids has an inseam length of 21.75 in.
- Size M (10–12) Kids has a weight of 5.1 oz. (144 g)
- Machine wash separately in cold, gentle cycle, remove promptly; do not use bleach or fabric softeners; tumble dry low
- Note: not intended for sleepwear
- Contains materials that meet the bluesign® criteria
- 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 BottomsBest Use | Multisport |
---|---|
Fabric | 87% recycled polyester/13% spandex (bluesign approved) |
Sun-Protective Fabric | Yes |
UPF Rating | 50 |
Moisture Wicking | Yes |
Underwear Weight | Midweight |
Inseam (in.) | 21.75 inches |
Gender | Kids' |
Sustainability | Contains materials that meet the bluesign® criteria Contains recycled materials 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.

