I'm about 6' and weight around 170, a skinny 170 if that makes any sense, and I buy all my O'Neill wetsuits in a medium. They are always a little tough getting on when brand new but the last thing you want is a wetsuit that's too big. You'll be perfect in a medium
i just had that happen to me...only it was for west wetsuits. i won a free west wetsuit and i ordered a small, only when it came to my house and tried it on did i realize it was way too small. i ordered a medium and to be honest i thought i was a xs but ordered the small just in case. im 5'7.5 140 and the small that i ordered that was too small, and it is suppossed to fit 5'8-5'10 135-155lbs. the medium that i got after wards that fits perfectly is supposed to fit between 5'9-5'11 150-170....Doesn't really make any sense, but hey it not fits.
the point im trying to say is, always order a size up if your not sure. it can never hurt
Oneill seems to be true to their size chart
Pinwheel: it does make me feel a little better being that you wear medium and weigh a little more than me.
Maybe the suit has never been tried on, but I was just surprised how hard it was to get the suit over my legs and feet (and I don't have big legs or feet). The short back zip is a little different but that wasnt really the problem.
I'm going to go ahead and keep it, it's hard to remember how tight my other wetsuits were when I first tried them on. I didn't know if there were any specific concerns with Oneill sizing, sounds like there isn't anything except personal preference.
I would keep it that is the most flexable suit oneill makes by far so you should be able to break it in I am 20 lbs over sized for oneills suits I wear not that big of a deal they end up the right size hence the reason all my suits are from them. Also a good fitting suit is probably the reason I am still not even close to getting out of a 3/2.
First off, no wetsuit needs breaking in. Your suit should fit snug, without extra room, but not overly tight. To tight and it will cut off your circulation reducing movement and making you colder. If you are within the weight and height specs, you should be good to go. Most likely you need a little practice putting it on and taking it off. Peel it off inside out when removing. If you're skin or the suit is damp, it will be harder to put on.