Fly up the trail and down the slope in your Helly Hansen Fly Pant base layer.

Wear the Helly Hansen Men's Fly Pant long underwear for aerobic activities in cool weather. These bottoms wick moisture and dry quickly, so you can sweat your way up a mountain or rush down a ski run and not feel clammy or chilled. They're also antimicrobial, which means they won't stink at the end of the day.

  • Reviews
  • Q & A

Not stretchy enough

  • Familiarity: I returned this product before using it
  • Fit: Runs small
  • Size Bought: M

I was expecting more stretch. The legs had a strange constricting quality which I did not enjoy, especially at the knees, where my motion felt hindered. Maybe the next size larger would have worked, if the waist wasn't too big, but I didn't want to take that chance. Full disclaimer: I am a woman, but almost all of my comfortable pants are mens'.

When it says it runs small, they mean it

  • Familiarity: I returned this product before using it
  • Fit: Runs small
  • Size Bought: medium

If you normally wear a medium, get a large. If you are on the larger side of medium, get the extra large.

The material, waistband, and workmanship all look pretty good though. It also has subtle trade markings!

Great base layer.

  • Familiarity: I gave it as a gift but have feedback to share
  • Fit: Runs small
  • Size Bought: Medium

My husband uses these during the winter as a base layer when he is working outdoors. Comfortable and warm.
Initially, I ordered a small. Returned, and reordered size medium.
His waist size is 32.


  • Familiarity: I've used it once or twice and have initial impressions
  • Fit: True to size
  • Size Bought: Medium

Excellent fit, almost as good as the Patagonia. Can't wait to try them at the mountain this winter.

I'm a bit confused.
In the size chart, which is the measurement for Medium size? Because the shirt will have the measurements for the 'letter' size, but not the pants.

Future thanks for the help.

Best Answer

The size chart for "lettered" sizes also contains measurements for waist, hip, and inseam. Use those for this item. Some H/H pants use numbered sizes, which would use the other size chart, but these ones don't.

Use in lots of weather

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

I used these a lot on ski touring days last season under shell pants when the weather wasn't super cold. Lately I've been using them on mountain runs in the morning when the air is still cold and crisp. They breath well, insulate well, and don't restrict at all. My latest outing with them was a half-marathon in the mountains that started at dawn. Temps were below freezing at the start and near 60 degrees at the end. If you have more questions about any of the gear feel free to contact me directly (google my name and my contact info is easy to fine).

-Joel Bettner, HH Ambassador

Use in lots of weather

Size runs smalls

  • Familiarity: I returned this product before using it
  • Fit: Runs small
  • Size Bought: small

I normally wear a small and I bout an Oakley base layer. the Oakley is a size small, and it fits perfectly. but this HH is seriously tight, so tight I could barley pull the baselayer up. So if you get this, get a size bigger.

what temp range would should I use these...

what temp range would should I use these for?

are they more like a tshirt weight or a little thicker like thin fleece pants?

I currently use some older Hot Chillys fleece type tights/long johns with a non insulated ski shell which has served me well.

I will be in CO skiing this Feb which is what I will use these for.

These are lightweight, so they are going to be closer to a tshirt weight than a fleece weight. As far as temperature range goes, that is fairly subjective, but you should be good in cool to cold weather.

Thanks Steven. Any recommendations for bottoms that are fleece weight? Sine my ski pants aren't insulated I think I'll need something a little warmer.

Great base layer, nothing unexpected

  • Familiarity: I've put it through the wringer

Size is true to fit (I usually take a medium in pants - 32-34" waist - and these mediums were a perfect fit), comfortable material, no bunching, and perfect weight to keep one warm on moderately cold days.....they are listed as "lightweight" layer, so those looking for some serious warmth may want to go heavy-weight......these work great for me though - I'm on season 3 or boarding with them as my go-to base, and I've never complained about being cold.

Overall: great product, fits true, price is well worth it. Buy 'em.

great product

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

Just as with the top, the pants also kept me warm and dry on the slopes. Great buy at a great sale price.

lasted through mad trials

  • Familiarity: I've put it through the wringer

For a basic base layer, I found these to be the longest lasting. I work as a hotel valet in Alaska. Running in the cold almost every winter day has put a lot of gear to the test and I have to say for warmth level these have passed the friction test. Burned through multiple patagonia cap 1 base layers. Not feeling the diff in warmth protection I'd recommend these over the patagonia. All my other base layers have worn holes in the crotch area where as my hellys from years ago look good as new.

Helly Hansen HHDry fabrication

See why Helly Hansen's HHDry, using LIFA Stay Dry Technology, is the best way to keep you dry during your outdoor adventures.

Nice set of pins

    Bought these to go with the Helly Hansen Dry Stripe Crew Top to form my thermal set for winter in Everest Basecamp region. Bottoms are nice and comfortable and appear strong. Nice and spacey for tall guys too.

    Very Nice Fit

      I love everything about the HH Fly Pants. For me the fit is spot on, the fabric is super quick to dry, and they do better than average with stink. The fabric runs/snags easily so keep away from sharp objects: Fingernails, velcro, etc., or you'll end up with a nice snag in your baselayer. I wouldn't hesitate to buy again.

      Performs great

        Good for anything. Helly Hansen knows. Happy with the purchase.

        Men's HHDry Fly Pant

        On body back view.

        Men's HHDry Fly Pant

        Men's HHDry Fly Pant

        On body front view.

        Men's HHDry Fly Pant

        Helly Hansen Baselayer HHDry Review

        Watch this review from a professional mountain guide on how this baselayer technology works to keep him dry and comfortable in all conditions.

        Men's HHDry Fly Pant

        This baselayer is made from Helly Hansen's Lifa Stay Dry Technology - check out how this proprietary fabrication keeps you the dry.