Men's Merino Running Briefs | Runderwear™ – Runderwear AU

Men's Merino Running Briefs - ADD ANY 3 ITEMS TO YOUR BAG SAVE 15%* more


Seamless Men's Running Briefs enhanced by the magic of Merino. Experience unrivalled comfort and performance.

  • Responsibly sourced, sustainable Merino with seamless design
  • Naturally regulates temperature in any conditions
  • Anti-bacterial, odour-resistant and removes sweat quickly
  • Super-fine, ultra-soft and non-itchy against the skin
  • As with all Runderwear products: Chafe-free, guaranteed

Colour: Grey

  • Grey


  • S
  • M
  • L
  • XL
  • XXL
Runderwear Men’s Merino Running Briefs are designed to deliver unrivalled comfort and performance. All the features of our classic Men's Running Briefs - seamless design, breathable, moisture-wicking and of course, chafe-free - enhanced by the magic of Merino; the world's best natural performance fibre


Merino wool comes from Merino sheep, who face scorching hot summers and bitterly cold winters in their natural Australian mountain habitat. As a result, their wool has evolved to have unmatched levels of temperature control - so our Merino range will keep you at the perfect temperature in any conditions

This intelligent, organic fibre also absorbs both odour-causing bacteria and moisture from your body, quickly. It traps the bacteria to make it odour-resistant and it can absorb up to 35% of its own weight before feeling wet, meaning you stay fresh and dry on your run

To prevent overheating the sheep are sheared once a year, so the fibre is sustainable and renewable. The fineness and softness of Merino is measured in Microns – at 18.5 Microns, Runderwear Merino is super-fine – making it ultra-soft and non-itchy against your skin

Fabric Composition:

45% Merino Wool
40% Polyester Thermocool™
10% Polyamide
5% Elastane

Product Care: 

  • Warm machine wash up to 40°C
  • Wash with similar colours
  • Do not tumble dry
  • Do not soak, bleach or dry clean
Size Guide
CMs 76-81 81-86 86-91 81-96 96-101
INCHES 30-32 32-34 34-36 36-38 38-40

Runderwear Help and Advice:

If you need any help or advice, you can contact Team Runderwear, we would love to hear from you!


Runderwear Shipping:

FREE shipping in Australia and New Zealand on all orders over $70

We aim to ship the majority of our Australian & New Zealand orders from our Australian warehouse in NSW. In the rare circumstance that we are unable to fulfil your order from our US warehouse, then we will dispatch your order from our UK warehouse on a tracked service at no extra cost. This should take 7-10 business days to arrive.

Shipping Option


Carrier Service

Delivery Time

Free Shipping - Orders Over $70


Australia Post Parcel

Typically 3-10 working days

Standard Shipping - Orders Under $70 $9.00
Australia Post Parcel
Typically 3-10 working days
Express Shipping- All Orders $10.00
Australia Post Express
Typically 2-5 working days

Runderwear Returns:

You can return any Runderwear Socks, Crop Tops, Support Bras, Base Layers to us within 14 days of purchase and can request a full refund or a product exchange.

Due to hygiene reasons we can not accept returns on underwear including Briefs, Hipsters, G-Strings, Hot Pants, Boxer Shorts and Tri Suits, if they have been worn.

In the unlikely event that your product becomes faulty, you may return your purchase for a full refund or exchange.

Please package your return appropriately and add in a note to let us know whether you require a refund or product exchange. Please pay the postage in full and send to Team Runderwear at the following address:

Runderwear Returns
PO Box 5090

Please email Team Runderwear at if you require any further help.

Customer Reviews

Based on 70 reviews
Only 45% merino!

I just received these "merino" wool underwear, thinking they would be merino wool. They fit fine, and I have yet to see how they perform with sweat and odor, but can they really credibly claim merino wool? They're 45% merino wool and 40% polyester, which I only discovered when looking at the actual garment. The website touts the benefits of merino wool as if the product is primarily merino. Coming back to the site, I can't seem to find the merino content listed anywhere. Perhaps, these should be advertised as polyester underwear, and they should have a full spread articulating the wonderful merits of polyester? Don't buy these if you're expecting to get a garment that is primarily merino wool.

Hey Teddy,

Thanks for your review, Our co-founder Jamie who is a marathon runner wanted to develop a pair of seamless merino underwear for his own running. Through years of development the selected yarn was a blend of merino and Thermocool which is a thermoregulation polyester (not regular polyester) keeping you cool when hot but also warm when running in colder environments. The yarn is a premium yarn from Südwolle.

I am looking forward to hearing your feedback after you have trialled and we of course take on board your comments and we must communicate the above clearer on our website. I really appreciate the feedback and look forward to yours.



Scotty B
Excellent Briefs

I bought these a while ago,but hadn't done a review until I wore them to give my honest opinion.....
I can honestly say I was totally suprised how good they really are. I put them on for a 13 mile hike ,which was a very hard trek ,with steep was very warm ,17c and sunny..I wore these for over 6 hours and never felt hot wearing them,and I felt like I had gone commando they were so brilliant..
No sweating in the private parts or creases of the legs nor was my waistband wet/damp from body heat..
Definitely 💯 recommend, really good value for money and hold everything in place too if you get me..
Would love too see them in black or khaki in the future for bit more choice..
Treat yourself, you won't regret it....

Richard A

I have bought these for a (yet to undertake) multi-day trek, but having tried them on, they are the best and most comfortable fit of any underwear I’ve tried.

Thank you for your review, We are pleased to hear that you are loving your Merino Underwear and they are the most comfortable underwear that you have tried.

Thank you for your purchases with Runderwear.

not great

bought a pair of these and a pair of the standard non-chafe briefs. The non-chafe are far superior and comfortable. The merino are sadly unusable for me

Thank you for your review, I am sorry to hear that you did not get along with the Merino Briefs and you prefer the original Briefs. If you have any queries please do not hesitate to get in touch.

Stuart Hatcher
Just the best rundies you can buy

these are quite simply the best running underwear item that you can buy and that i have owned and tried. they will last and last as a high quality high performance but of kit, the merino is a great addition to running briefs as it helps wick away and keep you dry. i've used these for marathons and ultra marathons and the performance levels as against other underwear over these distances are superior. there is a lot of great running underwear out there now, but if i was to hands down be asked for 1 recommendation only it would be these. yes there are expensive (the 3 pack makes them almost affordable...) but you get the sense of why they are after using them for a while, and as i say, they will last so the overall investment cost is probably better than inferior product and when you factor in comfort, well, who wouldn't pay any price for that. they feel great, no itching or scratching or chafing and wash up well. just the best rundies you can buy imho.

Thankyou for your lovely feedback, Great to hear that you are loving the Runderwear Merino Briefs and they are the best that you have tried. We love to hear this! Thankyou for your purchases with Runderwear!

Buy any 3 items from across our store and save 15%.

Promotional discount codes can be used in conjunction with this offer except on Anti Blister socks.

Full details available here.

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