What is a little confusing is that for Sprint and Olympic distance Tri’s the swims are 500 meters and 1500 meters ( the bike and run are also in meters ) when you get to the half Ironman they switch everything to miles 1.2 mile swim 56 mile bike and 13.1 mike run and double that for full Ironman. Also from Sprint to Olympic the swim is triple the distance but from Olympic to 1/2 Iron it’s only an additional ~430 meters.
Well, in the US they do. I would assume if you’re anywhere else in the world they use metric!