Wool in the summertime?  Only if it’s Icebreaker, whose running apparel keeps you cool and comfortable even during hot aerobic activity.  Not exactly what you expect from a sheep, huh?

Sonic Crew Shirt Features:

  • 150 g/m2 merino wool
  • Main panel fabric: 96% merino, 4% elastane.
  • Eyelet panels: 99% merino, 1% elastane
  • Raglan sleeves
  • Stash pocket at right waist
  • Reflective accents
  • Four color options
  • MSRP $80

 Sonic Shorts Features:

  • 150 g/m2 merino wool
  • 7” inseam (5” option also available)
  • Main panel fabric: 100% merino wool
  • Liner: 96% merino, 4% elastane
  • Eyelet mesh side panels for venting
  • Flatlock stitching
  • Interior waistband stash pocket
  • One color (black)
  • MSRP $80

icebreaker sonic crew

My Experience

Icebreaker is now a few generations into its specialized running apparel line, and each iteration has been an improvement over the previous.  While they aren’t quite perfect yet, this year’s Sonic crew and shorts make a compelling case that merino wool can be nearly the equal of modern tech fabrics in terms of comfort and performance.

The advantages of merino wool are well-established: it has outstanding natural odor resistance, and maintains its insulative ability even when wet.  It can be crafted in such a way as to make it very comfortable against the skin – which Icebreaker excels at – and also has natural moisture wicking properties to move sweat away from the skin.  Icebreaker apparel is ideal for wearing day after day, either when you’re away from home and packing light, or when you’re just too lazy to do laundry very often.

icebreaker sonic crew and shorts

Although merino is a wicking fabric, previous versions of Icebreaker’s running shirts tended to retain moisture a bit before evaporation, leading to a more rapid accumulation of wet spots than modern tech fabrics.  In that regard, the Sonic crew is a huge improvement: I’ve worn mine in 85 degree temps without getting the soggy buildup that my earlier Icebreaker shirts tended to develop. And because it’s made of Icebreaker’s lightest 150g fabric, it’s easy to wear as a baselayer when the weather gets cooler.

One component Icebreaker hasn’t quite improved is the stash pocket on the crew, which is very small and has no secure closure, so solid objects like a key or gel packet have been known to bounce out on long runs.  However, if you’re like me and don’t carry stuff in your shirt anyway, this quibble isn’t a problem.

After 10 miles at 80 degrees: just a trace of moisture condensation around the collar.

After 10 miles at 80 degrees: just a trace of moisture condensation around the collar.

Icebreaker’s Sonic shorts are made with the same 150g fabric, but their overall weight feels a bit heavier than lightweight performance fabrics.  However, they feel very soft against the skin, and transport moisture just as effectively as the Sonic shirt.  Ventilated side panels increase comfort on hot days, and the shorts also have a roomy cut that makes them well suited for multiple sports besides running.

The Sonic shorts have a stash pocket inside the waistband, but as with the shirt, it is only large enough for a key or single gel packet.  Runners vary in their preferences for cargo storage on shorts; if you like lots of places to stash things, you’ll need to tote an additional pack while wearing the Sonic shorts.

The Good:

  • Greatly improved moisture management
  • Comfortable feel for both shirt and shorts
  • Outstanding natural odor resistance

The Bad:

  • Shorts feel heavier than modern performance fabrics
  • Storage areas are lacking on both garments

The Bottom Line

Icebreaker’s running apparel continues to improve, and the Sonic crew is virtually the equivalent of modern tech fabrics.  The shorts are getting closer as well, but could benefit from lighter construction and added storage.

Buy Now: Available at Backcountry.com

About Author

Donald is a physical therapist, ultrarunner, barefoot aficionado, and father of three with more than 20 years of experience in endurance sports. When he's not training for ultramarathons, he enjoys hiking or slacklining with his family in Monterey County, CA.


  1. I have been using the Sonic crew for the last few weeks. I like the fabric and that it doesn’t stink like the tech fabrics. Butt for me the shirt retains to much moisture, in 70 degrees the shirt got soaking wet and stayed wet. So it get’s very heavy, drapes on my body and gives an uncomfortable feeling.I like wool in the winter butt not in the summer. Icebreaker should make this shirt even lighter, like the Patagonia wool 1.

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