I have an Apple Watch Sport since the 24.04. I used the watch to track a lot of workouts (running, cycling). I noticed during my first runs that the distance at the end was like 5-10% shorter than on Runtastic or Runkeeper. I ran this track a lot of times so I'm pretty sure that it is around 8KM. I always took my iPhone with me so that the Watch could use the GPS on the Phone. So in the last couple of days I went on three runs on the same track: 1. Apple Watch + iPhone (IMG_0119) 2. Apple Watch without iPhone (IMG_0118) 3. iPhone with Runtastic (Screenshot ...) I attached a photo of each run to this post. It's in German but you should get the data. It cleary shows me the Apple Watch without the iPhone is more accurate than with the iPhone. How can this be? It's absolutely ridiculous. Tracking the distance without GPS is probably much harder. Both are still shorter than the Runtastic data. So Apple got the hard thing pretty good but messed up the easy thing? How can this be? Of course the messed up distance tracking also messes up my pace (time per km). Also the activity calories are way lower than data on Runtastic. Runtastic data seems more accurate to me. When I go cycling for an hour the Activity App shows me around 350kcal (Active Calories), one hour run is 450kcal. So an activity that is way harder (running) only burns like 100kcal more? My Heart Rate is about 40-50bpm higher on the run. I spook to some people on Twitter who have similar issues. I already have my second Apple Watch (had a dent in the first, got AppleCare+) so I'm pretty sure it's not a hardware issue. Did Apple do their tests only indoors (ABC Video)? Did they forget to take it outside? It's probably an issue that they can fix pretty fast. Hope they know about it. Kathy Turlington should tell them.