REI Co-op Midweight Long Underwear Bottoms - Boys'
This product is not available. Good news: we have a newer version.
The soft and comfortable REI Midweight long underwear bottoms help keep your boy's legs warm when he ventures out to play in the snow or other cold-weather fun.
Shop newer version- Polyester fabric draws moisture away from the skin and dries quickly; peached finish creates a super soft feel
- With a UPF 50+ rating, fabric provides excellent protection against harmful ultraviolet rays
- Gusseted crotch; flat seams; elastic waist
- 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
| Best Use | Multisport |
|---|---|
| Fabric | 95% polyester/5% spandex |
| Sun-Protective Fabric | Yes |
| UPF Rating | 50 |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Underwear Weight | Midweight |
| Inseam (in.) | 25.5 inches |
| Gender | Boys' |
| Sustainability | From a Climate Label Certified brand |
| XXS (4-5) Kids | XS (6-7) Kids | S (8) Kids | M (10-12) Kids | L (14-16) Kids | XL (18) Kids | |
|---|---|---|---|---|---|---|
| Numerical Size | 4 - 5 | 6 - 7 | 8 | 10 - 12 | 14 - 16 | 18 |
| Height Range | 41 - 44 | 46.5 - 49.5 | 52 | 55.5 - 58.5 | 62.5 - 64 | 67 |
| Chest | 22 - 23 | 24 - 25.5 | 26.5 | 27.5 - 28.5 | 30.5 - 32 | 33.5 |
| Waist | 22 - 22.5 | 23 - 23.5 | 24.5 | 25.5 - 26.5 | 28 - 29.5 | 31 |
| Hip | 21 - 23 | 25 - 26.5 | 27 | 28 - 29 | 30.5 - 32 | 33.5 |
| Inseam | 17 - 18.75 | 20 - 23 | 24.5 | 25.5 - 27.5 | 30 - 31 | 31.5 |
Sizing Notes
Measurements are stated in inches unless otherwise indicated. Size chart values represent body measurements, not garment measurements.
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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quality product
I bought these for my 11 yr old son for our first ever backpacking trip. We were hoping for some hot summer weather but yah never know in the sierras; and good thing we packed these, we got hit with thunder/lightning, and a hale storm and these kept him warm for 4 days. We did get soaked throughout all our layers because our top layers were not that rain proof but at least we kept warm. The fit is perfect for him and the price was right. Since he is growing rapidly I'm not sure how long they'll fit him for but for the price I'm not too worried about it.
Fit and work GREAT!
Maybe I got last years model but I bought them at the beginning of the 2013/2014 ski season. I have an ultra skinny kid and they fit him great in waist and length. They work so well that he crashed one time and the pocket on the knee of his ski pants took in a bunch of snow that he did not know about. While eating lunch in the lodge, that started to melt. He had no idea his ski pant was wet at the knee until he felt it with his hand accidentally. They continued to keep him warm the rest of the day.
Waist is too big
I have purchased REI long underwear every year for my kids, but unfortunately the waist on the bottoms is just too big. They just fell off my son. The top that goes with it is great as usual, but please go back to the prior year's bottoms where the elastic in the waste actually bunched up a bit. My son was bummed as he prefers the material on these long underwear to all other options.
Knees are too thin for toddlers
I purchased two pair of these for my 3 year old son and the knees ripped after half a season of use.