LOVE this jacket! Bought it for snorkeling and swimming because I get cold even at water temps of 80F. According to the size chart I should have ordered a 6 but they didn't have that size. My measurements did fall within the size 4 ranges but my weight was over by 5-10lbs so I rolled the dice and ordered the 4. My frame is wider than average at the shoulders so my main concern was that it would be too tight through the shoulders for good comfortable range of motion and that it would be a half hour struggle to get it on. Well it fits great! It's nice and snug through the torso but I still had plenty of room in the shoulder area without it being loose, no tightness or pulling across the upper back, way easier to get on than my shorty suit, and it was super comfortable. Didn't feel restrictive at all when snorkeling or swimming. Some reviews mention it's difficult to zip up when sized according to the size chart, but in my opinion it's just how wetsuits fit. Its really not that hard and once it's zipped it's not an issue. No problems with the zipper coming unzipped or anything. Perfect for me as it kept the cool sea water out and keeping me warmer on long swims. Actually ended up wearing it in the pool too as it rained half our vacation so I spent many hours in it and had no issues!