Everyone giving great info. ...I would just add one other thing...since your looking at a 3mm, which is also the suit commonly used by surfers, make sure the suit you get is meant for SCUBA and not a surf suit...the suits meant for surfers have a different neoprene bubble make up..they arent meant to be at depth and they don't compress and expand back like the neoprene used in a scuba suit...they would work to keep you warm,,for one dive.