I'm 5'9", 140 lbs., chest 35", waist 29", hips 40.5". I ordered medium, and it fit well - they are long enough for my legs, not too small in the thigh or butt. I have a narrower waist, so there is a slight gap at the very top, but that happens on a lot of pants and leggings for me and can be resolved by tucking the matching jacket in. The material is thicker, but it doesn't feel restricting or too bulky anywhere, not even in the hip flexor area (I wore them around the house and stretched in them to check.) The pattern is beautiful and looks great with the jacket I ordered. I haven't field tested this, but I plan to wear it in Mexico this February for watersports and for summer boating in Idaho where the water and weather can be cooler. I'll see if its functional enough to slalom waterski in. This was a last minute add to my cart, but I'm excited for it as I often get cold. I wore a carve full-coverage bikini bottom underneath, and I didn't notice any "underwear lines" through the pants.

I’m 5’5” and about 125-130lbs and the Medium fits great. Normally, I would wear a small but the suggestion to size up was good. The tight and the matching jacket (small worked for this item) is perfect for open water swimming in water that is too warm for a full wet suit but too cold to stay out in any length of time with just a swim suit. It is great sun protection and also very flattering.