5-inch inseam trunks are the sweet spot.

5-inch inseam square-cut trunks with a built-in mesh liner. That’s the answer.

Anything longer than 7 inches flaps around your thighs and makes athletic legs look like tree trunks stuffed into fabric. Anything shorter than 5 inches is basically a speedo, which is fine if that’s your thing, but you asked about not riding up. The 5-inch cut hits mid-thigh, shows off your quads without being obnoxious, and the built-in liner keeps everything in place—no wedgie, no adjusting every time you get out of the water.

Look for a contoured pouch (brands like Chubbies, Bonobos, or outdoor brands like Patagonia do this well) and a drawstring that actually cinches. Avoid board shorts with a lace-up fly—those are for surfing, not sitting poolside. Stretch fabric helps too, but make sure the compression isn’t too tight. You want support, not a tourniquet.

Your quads will thank you.