I am 5'10 165lb -ish. I purchased a size 12 and it fits snug. I usually wear a dress size 8, swim suit bottom size L and top M, so I would order a size up. I dive in 80f water and this keeps me pretty warm.
This is exactly what I needed for spring paddling when a swim can get uncomfortable. The fit and comfort is perfection, and it's warm enough without being stifling. According to the size chart I would be a 6 but I bought an 8 because it's what was in stock, and it fits perfectly (large bust, short torso, extra long arms, 115 lbs). The onl... Read Morey thing I wish was different is the zipper, it could stand to be 2 inches longer and it would make getting in and out of this a lot easier. Right now I'm like Chris Farley changing in the airplane bathroom to get it on and off.