Smartwool Women’s Classic All-Season Merino Base Layer Long Sleeve review: an all-year-round top

Smartwool Women’s Classic All-Season Merino Base Layer: first impressions

It’s not an easy task to achieve high ethical production standards and also deliver top-end technical functionality when you’re making outdoor apparel from animal-sourced fabrics, but I think the Smartwool Women’s Classic All-Season Merino Base Layer delivers on both fronts. This high-performing, super comfortable base layer proudly boasts ZQ certification, which means the manufacturing process conforms to strict standards of animal welfare, environmental sustainability, fiber quality, traceability plus overall social responsibility.

The top’s Tencel Lyocell fibers are made from composite recycled cellulose, making the garment lightweight and super comfortable for a range of different active sports. Temperature regulation, odor resistance and moisture management are all key reasons why many people opt for Merino wool – but with this top users don’t suffer with the dampness that you sometimes experience with wool, thanks to this high-performing, recycled cellulose fiber. It feels nice against the skin, helps minimize awkward sweat patches and makes the garment ideal for wear in-between temperature fluctuations. I reckon this is a product for all seasons. 

However, I did feel that the sizing was somewhat generous, with extra room on the waist and arm length; the small top I was testing felt more like a size 12 – so this is worth bearing in mind if you’re after a more fitted top. 

Smartwool Women’s Classic All-Season Merino Base Layer: on the trails

I tested the Smartwool Women’s Classic All-Season Merino Base Layer on the fells of the Peak District. While I was walking, I felt it managed to balance the warmth generated from long uphill hikes against the chilly winter breeze, yet the powerful wicking performance of Smartwool’s ultralight fabric kept that icky “damp wool” feeling away. 

Fit

First things first – the Smartwool Women’s Classic All-Season Merino Base Layer was a lot bigger than I expected it to be. Despite ordering a Small, it was large across my shoulders, back length and arms, and felt more like a size 12 than a size 10. This seemed to chime with other buyers’ comments on Smartwool’s website too, so do factor this in. 

However, this needn’t be perceived as negative – I rather embraced the baggier, looser fit. It gave me the option to wear the garment over the top of other layers, which meant the product had extra versatility – I have enjoyed wearing it as a mid layer after finishing walks, and swapping it out when reaching summits on spring days. I do suggest sizing down, though, if you’re after a more true-to-fit base layer experience.

Comfort

Effective thermos-regulation and non-clingy sizing made this top an ideal product for those slightly warmer winter days. Far too often I make the mistake of starting a day in the hills by dressing for the weather at the edge of a breezy car park, only to find myself quickly getting hot and sweaty, de-layering and then rapidly cooling down because of a damp base layer (see also: Hiking layers: everything you need to know to keep yourself warm in all conditions). Yet on hikes up to Derwent Edge, the clever product composition meant I could happily keep this Smartwool top on all day, sometimes wearing it as a mid layer over other base layers. 

Materials & Care

Merino often wears well, then suffers in the heat and beat of a frantic washing machine drum, leading to unsightly holes appearing in the material. With the added Tencel, this top can be washed like a standard wool item on a cold and gentle cycle, though if you’re nervous about shrinkage, you can hand wash it – which can be a faff, but it helps extend the product’s life.

I’ve owned many Merino layers that have experienced a fair bit of abuse. Although I haven’t had this one for a decade, like my other wool base layers, I’m keen to prolong the life of the item, and make sure it can be worn over and over. As Merino wool can be washed less and aired to keep it smelling fresh, I’m excited to see how the quality of the product lasts being worn more often all year round. 

Design

The design is super minimalist, with just a small Smartwool logo and trim. I like that the top is super light, thanks to having no zip. I also love the texture of the Merino-Tencel material, which still feels like wool, but is highly breathable and comfortable against the skin.

With the larger-than-expected sizing, I found I could just pull the long sleeves up when I was walking up hills. The product does not have thumb loops, yet I felt the top performed well enough without them, and this wasn’t a feature fault that felt super important to me, as it has a more “casual” style than most base layers. 

Price

Being a high-quality garment, the Smartwool Women’s Classic All-Season Merino Base Layer comes with a fairly steep price tag, but its ultralight weight and all-year-round functionality makes it a worthy addition to your outdoor kit cupboard. 

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