Isobaa Merino Women’s 260 Merino Active Tights, 160 Merino Active Long Sleeve Crew, and 160 Merino Active Roll Neck
Merino wool has become one of the most dependable fabrics in endurance sport. While synthetic performance layers still dominate road running, many trail and ultra runners prefer merino for one simple reason: it works exceptionally well when you are out in the elements all day.
I have been using merino clothing for over a decade across ultras, long mountain days, and multi day hikes. Few materials regulate temperature as naturally, manage odour as effectively or remain comfortable during long days where my kit choice becomes more important with every passing hour.
Until now, all of my Isobaa long sleeve running and outdoor layers have been either the Women’s Merino 200 Long Sleeve Zip Neck or the Merino 200 Zip Neck Hoodie. Both use a heavier 200gsm superfine merino construction, and they have been consistently reliable pieces for colder days, hiking, and lower intensity winter movement. The zip neck in particular works well for venting on climbs, while the hoodie adds valuable warmth and protection when conditions deteriorate.
Ok, I might have a merino addiction!
While I have genuinely loved using both, switching to the lighter 160 weight layers has highlighted how much difference fabric weight makes when running. The reduced density noticeably improved my temperature regulation over long hours, allowing heat to escape more efficiently while still retaining merino’s comfort and odour resistance. As a result, the 160gsm pieces feel better balanced for running specifically, sitting more naturally as an active layer rather than a cold weather insulation piece.
Isobaa specialises in responsibly sourced merino apparel designed for active outdoor use rather than purely lifestyle wear. Alongside testing these garments for running, I’ve also used their socks for years, both on their own and layered as liners beneath neoprene or thicker socks for seriously boggy winter days.
This review looks at three pieces from Isobaa’s Active Collection:
- Women’s 260 Merino Active Tights (Navy)
- Women’s 160 Merino Active Long Sleeve Crew (Lime)
- Women’s 160 Merino Active Roll Neck (Charcoal Melange)
All three pieces use superfine merino blends designed to balance softness, durability, and stretch, a combination increasingly common in performance merino garments.
Features
Women’s 260 Merino Active Tights (Navy)
- 260g 18.5 micron superfine merino wool (96% merino, 4% elastane)
- Gusset construction to aid freedom of movement
- Designed for cold weather activities
- Self fabric waistband with internal adjuster drawstring/elastic
- Flatlock seams
- Side leg panel with open top thigh pocket with stretch binding
- Naturally soft, moisture wicking, odour resistant and breathable
- Embroidered Isobaa sheep logo
- Non mulesed merino
- Recycled and recyclable packaging
- Weight (size S): 225g
Women’s 160 Merino Active Long Sleeve Crew
- 160g nylon core spun superfine 18.5 micron merino wool blend
- Underarm gusset construction for freedom of movement
- Flatlock seams
- Thumb holes
- Scooped back hem for extra coverage
- Naturally soft, moisture wicking, odour resistant and breathable
- Embroidered Isobaa sheep logo
- Non mulesed merino
- Recycled and recyclable packaging
- Weight (size S): 167g
Women’s 160 Merino Active Roll Neck
- 160g nylon core spun superfine 18.5 micron merino wool blend
- Underarm gusset construction for movement
- Roll neck for cold weather activity
- Flatlock seams
- Thumb holes
- Scooped back hem for coverage
- Naturally soft, moisture wicking, odour resistant and breathable
- Embroidered Isobaa sheep logo
- Non mulesed merino
- Recycled and recyclable packaging
- Weight (size S): 173g
Women’s 260 Merino Active Tights
The first thing I noticed about the 260 tights is substance. At 260gsm, they sit in cold weather territory, closer to a thermal running tight than a lightweight legging. For winter trail running, early starts, or exposed mountain days, that added density immediately feels comforting rather than excessive.
On the move, the fabric delivers the classic merino advantage: warmth without overheating. Unlike fleece lined synthetics that trap heat aggressively, the tights regulate temperature dynamically. During long climbs they never felt stifling, yet the moment the pace dropped at the top or wind exposure increased, warmth returned quickly. This adaptive comfort is where merino still outperforms many technical fabrics for long duration running. They excel in our cold, damp British winter conditions, and, when paired with waterproof over-trousers, they have been weather-proof.
The fit is secure without feeling compressive. The gusseted construction allows unrestricted stride movement, and the flatlock seams remain unobtrusive even over multi hour outings. The thigh pocket is great for holding my phone or gloves without bounce. Importantly, the waistband stays comfortable over extended wear, avoiding the pressure points that can become noticeable deep into an ultra.
Durability is often questioned with merino, but the elastane blend here adds resilience. These feel designed for repeated use rather than occasional layering. I’ve worn and washed these tights many times in the last few weeks and they look and feel the same as out of the box.
Women’s 160 Merino Active Long Sleeve Crew
The 160 Long Sleeve Crew is the most versatile piece in the lineup. At 160gsm, it sits in the sweet spot between lightweight base layer and standalone running top. For most UK conditions, this is the top I reach for first.
The fabric feels exceptionally soft against the skin, something that matters so much to me. Merino’s ability to resist odour becomes immediately noticeable across consecutive days of use. Multi day adventures or travel runs benefit enormously from this quality, reducing the need to carry spare layers.
From a running perspective, the underarm gussets make a surprise difference. Arm swing feels unrestricted, and there is no pulling across the shoulders even when wearing a vest or pack. The thumb holes are particularly cosy during colder starts, adding warmth without needing gloves immediately or when the temperature dips.
What stands out most to me is how stable the temperature regulation feels, especially as a woman of a certain age. Synthetic tops often swing between too cold when wet and too warm during effort. This crew maintains a consistent comfort range, especially in variable weather. The scooped rear hem also prevents exposure when bending or climbing, a small but thoughtful design feature that proves valuable in real use. Both tops are long on me, and being able to pull them down over my bum gives me an extra layer of protection.
Women’s 160 Merino Active Roll Neck
The roll neck version builds on the same successful platform as the crew but shifts its focus toward colder environments. For winter running in exposed terrain, the added neck coverage significantly increases comfort, but can still be worn with a buff for added cosiness.
I’ve never worn a roll neck for running, but this one strikes a good compromise. The merino fabric remains light and breathable enough that heat escapes gradually rather than building excessively. When conditions turn windy or damp, pulling the neck up creates instant protection without needing an additional buff.
The thumb holes again extend sleeve coverage effectively, creating a semi glove effect that works surprisingly well in marginal temperatures. Layering is where the roll neck shines. Worn beneath a lightweight shell, it creates a highly adaptable cold weather system without bulk. The nylon core spun structure adds stretch and helps the garment retain shape, addressing one of the traditional weaknesses of pure merino layers.
If you feel the cold easily or spend long periods moving at lower intensity, this becomes an exceptionally useful winter staple.
Pros
- Great temperature regulation
- Excellent odour resistance – multi wears between washing.
- Comfort against skin
- Performs well when damp
- Natural breathability
- Non mulesed wool and recyclable packaging add ethical appeal when responsibly sourced.
Cons
- Lower abrasion resistance
- While comfortable when wet, merino dries slower than polyester fabrics.
- Higher cost
- Requires gentler washing and more attention than synthetic kit.
Conclusion
Isobaa’s Active Collection demonstrates how far performance wool clothing has evolved. These pieces are intentionally designed for active movement rather than casual layering marketed as technical apparel.
The 260 Merino Active Tights stand out as a superb cold weather running option, particularly for winter trails and long steady efforts. The 160 Long Sleeve Crew is arguably the most versatile item, capable of handling everything from daily runs to multi day adventures. Meanwhile, the 160 Roll Neck becomes a specialist favourite when temperatures drop and comfort becomes critical.
After more than ten years of running and hiking in merino, the appeal remains unchanged: when comfort, consistency and all day performance matter, merino continues to earn its place in my running wardrobe and Isobaa remains at the top of the pile.
Have you tried Isobaa Merino yet? Don’t agree with this review? What’s your opinion? Add your own comment below this review and share your experience and passion for running with others.
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About the author:
Kate Allen is the owner and Editor of RunUltra and a Mountain Leader. An experienced ultra runner, in her spare time she can be found either running or hiking around the hills of Cumbria, Yorkshire and the Lake District.
