How to Choose Base Layers

A good day outdoors starts with a good base layer. This soft, synthetic top from REI Co-op provides midweight warmth for comfortable layering on cold days. Thumbholes add a cozy feel.
Imported.
View all REI Co-op Women's Base Layer Tops| Best Use | Multisport |
|---|---|
| Shirt Type | T-shirt |
| Fabric | 92% recycled polyester/8% spandex (bluepass certified) |
| Sun-Protective Fabric | Yes |
| UPF Rating | 50+ |
| Moisture Wicking | Yes |
| Underwear Weight | Midweight |
| Sleeve Length | Long Sleeve |
| Thumbholes | Yes |
| Gender | Women's |
| Sustainability | Fair Trade Certified™ Factory Contains recycled materials Contains bluepass certified material From a Climate Label Certified brand |
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First off, I am usually a small but generally like to have a bit of room in a hiking shirt. This is a medium and it is definitely fitted in the arms and torso, how I would maybe assume a small would fit. Although it is a base layer so maybe many would want it super fitted? It is pretty long and the material is what I would call mid weight, but not necessarily super soft but comfy enough. It’s stretchy, wicks well and seems like it will hold up well through multiple washes. Feels like a great layering hiking shirt or an under layer for skiing. The thumb holes are nicely disguised if you don’t want to use them!
Comfortable and fabric regulates temperature well. Wore this for a 6-mile hike up to a fire tower and it kept me cool in the sun and warm when the wind was ripping. I like the thumb loopholes and the way it fits my shoulders and arms, which are broad considering my size. It’s snug around the neck as you can see in the pictures. Torso length is long enough to stay put under backpacking straps. Not sure how long the material will last, as sometimes synthetic clothes do get stinky with time, but for now it’s been a solid add to my backpacking getup.
This base layer has been a solid find for the cooler fall days. It fits really well overall, and while it's longer than I expected since I grab a large for the fit, that length actually makes it super easy to tuck in. It works perfectly as a layer under other clothes, but it's also great to just throw on by itself for a casual hike or a walk outside when the air is crisp. One thing to note is that the fabric does have a scratchy feel, so if you're sensitive to textures, it might not be the best choice.
Great long sleeve t shirt for chilly weather. Fabric is soft and cozy but also lightweight. I like the substantial thumb holes. Fits well, I am normally an XS for tops, got a small for a looser fit and it feels just right.
I love the soft feel of this base layer—it has the feel of a natural fiber, despite being a moisture-wicking tech fabric. The weight is also perfect—heavy enough to be warm on a ski day, but light enough not to feel suffocating!


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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.

