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Smartwool PhD Outdoor Light Mini Socks

rated 4.5 of 5 stars
photo: Smartwool PhD Outdoor Light Mini Socks hiking/backpacking sock

Smartwool makes some comfortable, cushioned, and breathable merino wool socks that people rave about, but in my opinion, may not be the best merino socks out there.


  • Brand name
  • Comfort
  • Breathability


  • Less durable than other brands
  • Initial Piling

Smartwool makes some comfortable, cushioned, and breathable merino wool socks that people rave about, but in my opinion, may not be the best merino socks out there.

I'm evaluating these socks against five other pairs of socks that I've worn over the last few years.

These socks look great and fit great—no excess, no bulging, no binding, just a great fit. The are comfortable right out of the packaging.  

The socks have a decent amount of elastic and weaving to create a supportive feel. There is extra padding in the toe and heal, cushioning along the arch, and adequate elastic around the ankle. 

They are not water resistant, but one of the benefits of these socks is that they are wicking and dry quickly. They hold up to hand wringing too, which is important when you need to wash them in the wilderness.

They are easy to use and easy to maintain/clean. I typically turn them inside out and throw them into the washer and then the dryer. No special treatment. Initially there was some piling, but now the socks have shed the stubble. 

They do keep you warm when it is cold and cool when it is hot. The socks are woven less tight than other brands so they ventilate or breath nicely. I've owned various models of these socks. The earlier models did not last very long and it was easy to wear holes in them. The newer models have improved in quality and durability. In hotter weather I tend to choose these socks for their breathability. 

People rave about Smartwool socks. However, I think that the competition has increased and there are now better brands. My Smartwool socks have not held up as well as my Darn Tough, Injinji, or Feetures socks.

Overall, a decent pair of socks for daily use or outdoor use. 

I rate these socks as fourth among the six socks that I am reviewing.

I've owned these socks for about six years and have used them over 100 days in the outdoors and probably 200 days for daily use. I rotate them regularly with my other merino wool socks.

Check out my other reviews of six different socks.



Source: bought it new
Price Paid: $14

An excellent Merino wool sock with extra cushioning at the toe and heel. Mesh areas for enhanced breathability. Great for hiking, backpacking, trail running, and cycling.


  • Cushioned heel and toe
  • Breathable
  • Merino wool


  • None

Smartwool has hit the nail on the head again with their Merino wool PhD Outdoor Light Mini socks. These Merino wool socks are packed full of interesting details that pushed them into my excellent rating.

Smartwool has blended Merino wool, Nylon, and Elastane for the yarn in these outdoor socks. To start they utilize what Smartwool calls their Indestructawool technology in the toe and heel. This weaving technique provides for extra cushioning in these areas and also increases durability.

The areas on the top of the sock and under the arch feature a mesh ventilation system and an elastic X pattern over the top of the sock provides stretch and helps keep the sock from moving around during activity. A seamless toe and padded Achilles area complete the socks features.

I received a pair of these socks for testing at the beginning of August and have worn them mountain biking, hiking, backpacking, and in the gym. Since I hike and backpack in either trail runners or low cut hiking boots I prefer a micro sock. The fit of a men's large was correct for my size 9 feet. The stretchiness of the sock provides a nice snug fit without being tight.

Slipping the socks on I can immediately feel the extra cushioning in the toe and heel. The padded area around my Achilles adds additional comfort during activity and also helps to keep the socks from sliding down into the shoe. Even on the hottest August days on the John Muir Trail, the mesh areas did a great job of getting rid of heat and moisture. The socks would barely be damp at the end of a long day on the trail.

The usual side benefit of a Merino wool sock, not absorbing odors, was greatly appreciated on several backpacking trips. After four months of use and many washings, these mini socks still look and feel like new. The PhD Outdoor Light series are available in micro, mini, mid crew, and crew to fit any type of shoe or boot. All Smartwool socks come with a 2-year satisfaction guarantee.



  • Color:Light gray, Taupe, Charcoal, Loden
  • Price: $17.95


Source: tested or reviewed it for the manufacturer (I kept the product after testing.)

Disclosure: The author of this review received a sample of the product from the brand or its representative in exchange for a review.

These socks are awesome! I bought them because I didn't want a ton of sock hanging out above my boots in the summer time and because they were so comfortable. 

I've worn them fairly regularly over the past 2 years. They still fit very well and my foot doesn't slide around in them due to the strategically placed elastic (which hasn't worn out yet). The reinforced areas really help cushion my foot and wick away moisture while the thinner material on the top of the sock really lets your foot breathe and not overheat.

The wool-on-wool technology is very durable and have I noticed very little pilling up of the wool on the inside of the socks after lots of wear-- unlike my "regular" SmartWools which all have thin spots at the balls and heels of my feet where the wool has been worn away. 

An added bonus is they don't retain stinky foot smell, which is a relief to my tentmate while we're on the trail!

Price Paid: Bought on sale

A good sock, for trail runners.


  • Solid Smartwool construction


  • Can't wear these with boots

I am relatively new to the trail runner game, but having bought my first pair about a year ago, thought I needed socks to go with and these fit the bill.

Like other Smartwool socks, these are constructed of really good wool and yet light enough so your foot doesn't get hot. That being said, the socks are a bit one dimensional as they only go up slightly past your ankle bone so if you have any "high tops" or boots, they will chafe on your bare skin.

Overall, another quality product from Smartwool.

Source: bought it new

These socks are comfortable and great to wear all year round.


  • Comfort


  • Price

I love my SmartWool socks, I have several pairs of all different kinds.  I think the PhD Mini Crew are my favorite because I can wear them all year round.  They are so comfortable and they last for a long time.  They have been through many washings and have held up great.  

The only downside to SmartWool is the price. They keep getting more expensive as the years go on. Great socks though.

Source: bought it new
Price Paid: $7.95

Super comfortable, even without a liner. Great for day hikes.


  • Thin
  • Uncumbersome

These are great socks for day hikes. The only reason I wouldn't wear them for long distance hikes is because of the false sense of security I get from long socks protecting me from tics. If it's hot out and you need a pair of socks that will keep you cool and dry, reach for these. SmartWool never fails.

I not only wear PhD's on the trail, I wear them every day at work. I am on my feet about ten hours a day. At fifty years and god knows how many miles my feet need a lot of tender loving care.

My feet sweat a lot which is hard on socks. PhD's are the toughest I have ever had and they make my feet happy.

Price Paid: $16

I have used this sock and its adrenaline predecessor over the last 5+ summers and find them very comfortable and wearing well in light hiking boots.  Recommended.

Price Paid: about $13

Lightweight and very comfortable.

Really love these socks. Have ordered more varying colors.

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Price MSRP: $16.95
Current Retail: $18.95
Historic Range: $4.24-$18.95
Reviewers Paid: $13.00-$16.00
Price MSRP: $16.95
Current Retail: $17.95-$18.95
Historic Range: $7.83-$22.48
Reviewers Paid: $7.95
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