Smartwool PhD Outdoor Light Mini Socks

Runners and cross-fitters agree: the Smartwool PhD Outdoor Light Mini Socks are one of the most comfortable performance socks available.

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They may look basic outside, but the Smartwool PhD Outdoor Light Mini Socks are a performance machine. The Merino wool blend is durable as they use a proprietary Indestructawool™ fabric technology. Moreover, the lightweight fabric and mesh venting offer industry-leading breathability. By keeping your feet dry in Merino wool socks, you’ll prevent dreaded foot odor. As a result, your socks won’t stink either!

Further, performance would mean nothing without comfort. And, we must say, these socks are built for comfort. Smartwool’s 4 Degree™ elite fit system ensures minimal slippage, reducing the chance of blisters. Secondly, the light cushioning around the heel and under the toe minimizes your foot’s stress impact. Finally, Smartwool has even incorporated a Virtually Seamless™ toe for maximum comfort.

In other words, every aspect of this sock is crafted with your performance and comfort in mind. 

To sum up, the Smartwool PhD Outdoor Light Mini Socks are one of our favorite all-around Merino wool socks on the market. Don’t be scared by the higher price point, though. It may be on the expensive end of the sock spectrum. Still, it’s relatively affordable on the Merino wool sock spectrum.

View Smartwool Sizing Charts & Company Profile

Smartwool PhD Outdoor Light Mini Socks – Specs & Features:

  • 58% Merino wool/40% nylon/2% Elastane
  • Lightweight fabric with improved breathability and durability properties (Indestructawool™)
  • Light cushioning high impact areas
  • Mid-ankle height (slightly lower than 1/4 crew) – 3.75 in.
  • Maximum comfort with 4 Degree™ elite fit system & Virtually Seamless™ toe
  • 4 colors available
    • black, navy, chestnut, & fossil


  • Incredibly breathable due to lightweight fabric & mesh zones
  • Durable Merino wool blend that improves sock life
  • Virtually Seamless™ toe minimizes discomfort, especially for people with sensory issues


  • User-reported manufacturing inconsistencies. However, these issues are typically covered by Smartwool’s comprehensive warranty.
  • The fabric behind the heel may wear prematurely.

Best For:

Adventure | Casual | Hiking | Running | Training | Travel

Featured In:

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Disclaimer: Merino Wool Gear DOES NOT sponsor products. However, as an Amazon Associates Member, we may earn a commission from qualifying purchases.

Additional information

Merino Percentage

50-64% Merino Wool

Fabric Density (gsm)

145 – 180 Ultralight

Sock Height

Lower-ankle (low-cut)

Sock Cushion & Padding Level

Light Cushion


Casual, Running, Hiking, Adventure, Training, Travel

Colors Available

Black, Brown, Gray, Navy, Tan