For hot yoga, wear a light mesh brief or short-leg mesh boxer brief in a quick-drying stretch fabric, or lined split-side shorts that need nothing underneath. For the sauna, follow the house rules: where clothing is allowed, a quick-dry swim brief or trunk is the tidiest choice, and cotton underwear is the one thing to leave in your locker.
Why heat changes the rules
A heated studio or a sauna cabin puts your underwear through more in an hour than a normal day does in twelve. You sweat steadily, the air stays warm so nothing dries on its own, and in yoga you hold deep folds and wide stances that pull on every seam. The fabric that feels lovely on a cool morning can turn heavy, clingy and see-through once it is soaked.
So the questions are simple: does it let air through, does it dry fast, does it stay in place when you stretch, and does it still look decent when it is wet? Everything below comes back to those four points.
Hot yoga: what to wear under (or instead of) your shorts
In a hot class you want as little bulk as possible. A brief or a short-leg boxer brief sits close to the body, so nothing bunches when you move from a forward fold into a twist. Mesh is the natural pick here because air can pass straight through the fabric instead of trapping warmth against your skin.
- Mesh briefs for the lightest feel and the most freedom at the hips. Our Mesh Sport Briefs combine 80% polyamide and 20% elastane with mesh panels, a wide low-rise waistband and tagless laser-cut edges.
- Short-leg mesh boxer briefs if you prefer some coverage on the thighs. The Mesh Boxer Briefs are all-over mesh with a roomy pouch and come in 12 colours.
- Lined shorts, no underwear if you like a single layer. The Split-Side Lounge Shorts are silky and light, with deep side splits for leg room and a built-in liner, so you can skip underwear entirely.
Whatever you choose, it should feel snug on dry skin. Fabric relaxes a little once it is wet, and a loose pair will start to shift halfway through class. For more on how different cuts behave in deep poses, see our guide to underwear for yoga and stretching.
The sauna: check the rules first
Sauna etiquette varies a lot between countries and venues. Many saunas in Germany, the Netherlands and Switzerland are textile-free, with only a towel to sit on. Gyms, hotels and spas in the US and UK more often ask you to wear swimwear. Read the sign at the door or ask at reception before you go in.
Where clothing is expected, regular underwear is rarely the right call. Swimwear is made to get wet and dry again, and it moves easily between the sauna, the cold plunge and the pool. Three practical options:
- Mesh swim briefs: the Mesh Swim Briefs use a fine, quick-drying mesh with an adjustable drawstring, a double-layer contoured pouch and no tag to scratch when you lean back on the bench.
- Square-leg trunks: the Square-Leg Swim Trunks are 82% polyamide and 18% spandex with four-way stretch and a drawstring, a good middle ground if you want a bit more coverage.
- Trunks with a pocket: the Quick-Dry Swim Trunks add a zippered pocket for a locker key, plus an elastic waistband with drawstring.
Fabric comparison for hot sessions
| Fabric | In the heat | Best use |
|---|---|---|
| Polyamide-elastane mesh | Lets air through, dries quickly, stretches with you | Hot yoga, heated pilates, warm gyms |
| Polyamide-spandex swim fabric | Made to get wet and dry again quickly | Sauna (where allowed), steam room, pool |
| Silky lightweight shorts with liner | One thin layer, very little to dry | Hot yoga for men who skip underwear |
| Plain cotton | Soaks up sweat, gets heavy and stays damp | Save it for after class |
If you want the bigger picture on how mesh is made and styled, our article on mesh underwear for men goes deeper.
What to skip
- Thick cotton boxers. They hold water, sag and stay cold and clammy afterwards.
- Loose woven boxers. The fabric rides up in inversions and gets in the way.
- Light colours in thin fabric. Pale, unlined pieces can turn see-through when wet. Darker shades or lined swimwear are safer for shared spaces.
- Anything with stiff tags or thick seams. Heat and sweat make small irritations feel much bigger.
- Your everyday pair straight into the sauna. Many venues do not allow it, and it rarely looks good once soaked.
After class: a quick routine
Pack a dry pair to change into, because sitting in damp fabric on the way home is nobody's favourite part of the day. Rinse sweaty mesh or swimwear in cool water as soon as you can, then wash it on a gentle cycle and let it air-dry flat or on a hanger rather than in a hot dryer. Our guide on how to wash men's underwear has more tips for keeping elastic in good shape.
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Frequently asked questions
Should I wear underwear to hot yoga?
Yes, unless your shorts have a built-in liner. A snug mesh brief or short-leg boxer brief keeps everything in place and dries quickly. If your shorts are lined, one layer is often more comfortable.
Can I wear my normal underwear in the sauna?
It is best not to. Many saunas are textile-free, and those that allow clothing usually expect swimwear. A quick-dry swim brief or trunk is designed to be wet and looks neater than underwear.
Is mesh underwear see-through when wet?
Fine mesh is light by design, so darker colours give more coverage than pale ones. For shared spaces like steam rooms, swimwear with a double-layer pouch is the more discreet choice.
Which size should I pick for hot sessions?
Go with your usual size for a snug fit. Wet fabric relaxes slightly, so a pair that already feels loose when dry will start to move around during class.
Find your pair for the heat
Browse our sportswear collection for training and hot yoga, the mesh underwear range for maximum airflow, or our men's swimwear for the sauna and pool. Every order ships in discreet packaging.
