That is a very relative statement. It varies completely from person to person. Some people are runners, some are cyclists, and some are swimmers. Whatever you suck at becomes the hardest leg of the race. The swim is by far the easiest part for me. I think they should increase the swim on the Ironman and shorten the run to balance it out. Running a marathon is quite a feat, all by itself and takes at least twice as long as the swim. Also notice that the swim, by comparison, takes the shortest amount of time in any triathlon (sprint, Olympic, or Iron distance).