The Icebreaker ZoneKnit Merino Shorts Are the Best Running Shorts I’ve Ever Tried

Lightweight, super breathable, incredibly comfortable — the ZoneKnit Merino Shorts check all the boxes

September 18, 2023 12:12 pm
Icebreaker merino zoneknit shorts hero
If you want a pair of lightweight, exceptionally breathable, super comfortable shorts for running, you can end your search right now.

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I’ve tried many pairs of running shorts over the years, and for the most part, they’ve all been very similar. They’re made with lightweight, sweat-wicking synthetic fabrics that felt reasonably comfortable while running, but aside from different colorways and pocket layouts, they weren’t particularly noteworthy. After testing a pair of Icebreaker ZoneKnit Merino Shorts this summer, though, my whole outlook on performance running apparel has changed. Goodbye, synthetic fabrics — I’m running in wool from here on out.

I’m certainly not the first person to sing the praises of merino wool. Merino is a specific variety of wool that comes from merino sheep, a breed that thrives in harsh environments with both very hot and very cold conditions. Merino wool allows the sheep to stay comfortable in these temperature extremes, and when processed into a fabric, the material has a whole host of benefits. It resists odors, vents hot air and moisture when you sweat, retains heat when it’s cold, and even keeps you warm when it’s wet. In terms of versatility, no other fabric comes close. It’s an ideal textile for high-intensity outdoor activities like running, and the Icebreaker ZoneKnit Merino Shorts prove it.

Design and Materials

The Icebreaker Merino Shorts are designed specifically for running, and they’re made from a blend of Tencel (a fabric derived from wood pulp) and merino wool. In addition to merino wool’s performance properties, Tencel offers good breathability and a very soft texture. The shorts feature a brief-style internal liner, and they have an elastic waistband with an external drawcord. At the back of the waistband, there’s a small zippered pocket, and on the right side of the shorts, there’s an elasticated stash pocket with a small flap closure — it’s sized for securely holding a phone. 


I’ve had my pair of Icebreaker shorts for a few months, and I’ve worn them on many runs in my neighborhood and on trails in a state park near my apartment. I live in Los Angeles, so almost all of my runs have taken place in warm, sunny weather. Because they’re so breezy and comfortable, I’ve also worn my Icebreaker shorts while working at my desk at home.

What We Like

Soft, Comfortable Fabric: It was the first thing I noticed as soon as I pulled my shorts out of the box — they feel seriously soft against the skin. Comfort-wise, the Tencel-merino blend is lightyears ahead of the typical synthetic fabrics you find in workout apparel. There’s no plasticky hand feel or clinginess, and none of the scratchiness you might get with old-school wool apparel (like that Christmas sweater sitting in the back of your drawer). The shorts are so soft, that I even pressed them into service as loungewear. I put them on first thing in the morning and wore them for hours until I went for a midday run.

Really Light: These shorts are light. They weigh just over 6 ounces for a medium pair, according to Icebreaker, and my size small pair weighed 5.4 ounces. Their low weight combined with their stellar breathability (more on that below) gives them a feathery feel, and it seemed like they disappeared on my body while running. The 5.5-inch inseam kept them out of the way (no extra fabric flapping around), and overall, I barely thought about them after I put them on — a compliment, in my book.

Super Breathable: The Tencel-merino fabric breathes super well. I still got sweaty on my runs, but I never felt overly steamy. The porous fabric allowed even gentle breezes (and the forward motion of running) to create a cooling effect that kept me comfortable.

Doesn’t Stink: Many brands claim their products can be worn multiple times without washing, but most of my running clothes get pretty gross post-run. In my experience, synthetic fabrics dry quickly but take on an unpleasant odor after I sweat in them, and the smell seems to get worse if I run in them again. The Icebreaker shorts are that rare piece of apparel that doesn’t — no, really — need post-run washing. Even when I soaked mine with sweat, the shorts had no odor after air-drying outside. I felt totally fine wearing them multiple times between washes.

What We Don’t Like

Lack of Side Pockets: For running, these shorts had just enough storage. The elastic side pocket securely held my phone (although it did bounce around a bit while running), and the rear zippered pocket can hold small, lightweight items like a key or a couple of running gels. I did wish for at least one open side pocket. It would have made these shorts more versatile for casual wear. But that’s not what they’re designed for, and the additional pocket material would just add weight when running, so I understand why that feature didn’t make it into the final design.

Liner Irritation: For the most part, I had no issues with the liner. The Tencel-merino liner fabric felt breezy and comfortable, just like the rest of the shorts. However, on a couple of my test runs, the edge of the liner started to dig into my thigh, which required some strategic re-adjustment (not an easy thing to do in public). A longer, boxer-brief style liner might alleviate that issue, at the cost of increased weight.

Price: At $120 per pair, these shorts are expensive. I think they’re worth it for the performance benefits, but I recognize that this price point is beyond what many runners can afford to pay.


If you want a pair of lightweight, exceptionally breathable, super comfortable shorts for running, you can end your search right now. Just grab these. Although they’re pricey, you can get a ton of use out of them. While other, lesser shorts might need to head straight to the laundry hamper after a run, these shorts can see you through multiple workouts before they need a wash. That means you can get by with just one or two pairs. You’ll wonder why you ever bothered with plastic running shorts in the first place once you put these on for a run.

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