I wore these under long skirts in tropical Malaysia and Singapore and didn't feel uncomfortable in them at all. The fabric breathes well and I didn't feel like I was wearing anything more than underwear, even though they cover the thighs. You can wear them without underwear. It was in the 90s F and 99% humidity, and I didn't notice I wear wearing them. There was no air conditioning and I was sweating a ton but no problem with the slip shorts. Also completely effective at preventing chafing. Note: I wear a size 10/12 pants, so I got the large and it was too small by a lot, unless you want a control garment which I didn't. After a couple of exchanges (free) I ended up with the 2XL which fit perfectly without squeezing. So comfortable!