I've owned a number of premium underwear brands, including Y's own SilverAir Merino variety. The fit of these is pretty much the same, which is to say it's very good. Enough support for workouts and HIIT, but not too much so that it's still very comfortable to wear as a daily driver. In fact, they are one of the most comfy boxer briefs I've ever worn. Compared to the merino underwear, these are a lot lighter and airier. The merinos are great to wear as travel underwear, as well as for gym days. These new ones would be equally good for gym days, but I'd feel a lot better about running in them since they're so much lighter. I can't attest to the durability of these yet since they're brand new, but because they are so thin and light, I hope they hold up as well as some of my other premium activewear. We'll see! Otherwise, highly recommended.

I ordered these because you were out of stock (for a long time) with the S size Merino Wool ones that I love. (Seriously.. after 3 years of wearing still my favourite pair. And I ordered more of them earlier) Your contact said I should try these ultra thin ones. Especially with the hot weather here, but I feel like the fit is a tad different. It feels like the waist is a little higher?! And I don’t like the fly, I don’t need it and not love it. So.. the next time, I will go back to the Merino Wool ones.

Nothing to add. Title says it all

I have tried a handful of top merino underwear brands. Y athletics are my absolute favorite. Super comfortable, breathable with a great fit. I will definitely be purchasing more in the future.

I wish the blue was more vibrant, but even still, comfortable and true to sizing chart. They do ride up on the legs a little more than the regular weight underwear. So that can be a little frustrating. But if you’re quarantined on the couch, they’re great to lounge around in!