These neoprene shorts from Ion are a perfect solution if you want to be just a bit warmer than wearing a bikini. Short enough so you don't get weird tan lines on your legs, but not "Brazilian cut" either. These fit like your favorite yoga or workout shorts, just made out of neoprene to keep you warm. The slightly higher rise waist band help keep them up were they belong, and can be folded over if you don't want it quite so high. Add a long sleeve neoprene top and you are just as warm as wearing a shorty wetsuit, but with a lot more versatility (and a lot more comfort if you are tall).
Fit is true to size - with an XL being equivalent to a US Women's size 12.