Code: WINTER50—Spend $250, Save $50 »

Out of Stock

Item # CST0217

Don't worry though, we have a lot more Bike Socks in stock than that.

View Similar Products
Item # CST0217


Just as we have our favorite bibs, we definitely have our favorite socks. In cold weather, when we head for the sock drawer we go looking for a pair of socks made from Merino wool. Our comfort, and sometimes our sanity, depends on it.

The Castelli Merino Socks have some technical details that make them as good as any we've ever seen. Ribs at the ankle and compression elastic at the arch keep the socks from bunching up and cutting off circulation or causing blisters. The 9cm cuff is slightly longer than the traditional 7.5cm cuff, giving the socks a stylish look that aficionados of either long or short cuffs should find appealing.

The Castelli Merino Socks come in Black and in three sizes -- Small/Medium, Large/X-Large, and XX-Large.

Tech Specs

Recommended Use:
cold weather cycling, running, hiking

Reviews & Community


Write a review

    Add a:
  • Photos
  • Videos

No file chosen

Rather attach a photo from your computer?


Product Fit:

Runs smallTrue to sizeRuns large

Add Your Size


Height (ft, in):

Weight (lbs):

Size Purchased:

Only jpg, jpeg, png, gif or bmp files please.

Submit ReviewCancel

Here's what others have to say...

Avg. ride time: 3h 39m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Soft and warm

  • Gender:Male
  • Familiarity:I've used it once or twice and have initial impressions

They're socks . . . I get that, but with 5-7 inches of new snow arriving tonight, the merino wool will be appreciated in the morning. I've read that they run small. I used the size chart and had no issue -- I wear a 45-46 shoe and the XXL are perfect.


Great cold weather sock. Low ankle.

  • Familiarity:I've put it through the wringer
  • Fit:True to size

Nothing better than merino wool socks for cool/cold weather days. These socks are warm, soft and comfortable. The only negative is is that the ankle is low which can leave skin exposed between the sock and a leg warmer or tights.

Avg. ride time: 18m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Warm, they do shrink

  • Familiarity:I've put it through the wringer

These are The Bomb. I bought a pair of these, and a pair of the Castelli Thermolite, and have concluded that these are warmer. They also deal with sweat better under my Diluvio Shoe Covers, not letting my feet get cold when I do indeed sweat. The Thermolite socks are good but these are better.

I bought the L/XL for my Shimano size 43 foot, and will probably buy XXL next time, to accommodate shrinking from washing.


The white color is really cream.

    Castelli socks are a work of art. The quality is 10/10. Made in Italy. These are medium thick.

    I use wool socks almost year-round. Wool offers the best wicking material and zero odor (naturally). Wool is a superfabric!

    The color of these merino wool socks is CREAM not white (or dirty yellow) -which is totally fine with me. This is the natural color of wool that is not processed with bleach chemicals.

    Sizing: I wear a 45.5 shoe in Sidi (10.5-11.0 USA). I bought these socks in L/XL and they just fit. The XXL would have been better. If you wear a 45+ shoe definitely buy the XXL.


    Merino wool is perfect for cycling

    • Familiarity:I've put it through the wringer

    Never used merino wool socks until I ordered my 1st pair of Capo's from Backcountry. Was so happy with that, so I decided to try out this Castelli version. Very happy with these also. My shoes are 43 (8.5-9). Since on my prior experience with merino wool, I noticed a bit of shrinkage after 1st washing, I ordered the L/XL to allow for shrinkage and I am happy I did.

    Prior review mentioned it was not truly "white-white" and I agree. This is really an "off-white" or "dirty--white" or "light-cream". However, I did not care about the color since I just wanted it for the merino properties

    How thick are these socks? Looking for a...

    How thick are these socks? Looking for a less bulky merino wool sock.

    Best Answer

    These are a shy thicker than a standard thin sock that everybody rides. That said, they are just a tad thicker than a traditional everyday sock, but not crazy thick like some wool socks that leave you needing a larger shoe size. They are legit, and found that I do not use my shoe covers in colder weather, because these shield off the wind/cold. I need a new pair also, as my 4 legged friend chose to chew them up :)


    the white ones aren't white

    • Gender:Male
    • Familiarity:I've put it through the wringer

    I own the black socks and love them. You can't beat Merino wool for warm and cool weather riding. However, I just ordered the white ones and, contrary to the picture, they aren't white. More of a dirty yellow color, kind of like your grandfather's sweat-stained undershirt, so I sent 'em back. Customer service was great as usual.


    Great Socks!

      I love these socks. I live in Louisiana, so they provide the perfect blend of warmth and breathability for our climate.


      Love em!

        Love these socks. They look good and are warm. You know they are good winter socks when it's cold outside and you didn't think about your feet once during the ride. I would say they are good 37'-70' weather socks and since they are merino they breath well.