With lavacore the issue was "poor" fit. This is all laid out in my review. The breathable/lycra combo material is just not as stretchy as the ultra-thin neoprene and so some areas are tight and some are not, so it allows water flushing through. Underneath a wetsuit, it is OK and of course warmer than nothing because you do have a second layer. The OP seemed to want lightweight primary exposure protection for travel. If so, frogskins are a better option than lavacore based on my experience with both.