Has anyone using the apple watch for running found that the GPS is inaccurate?I have a set 5km route but the Apple Watch shows that I have gone 7kms

There is no GPS in the Apple Watch. If you're not carrying your phone with you, it will not be accurate until you've done several runs with your phone to calibrate the watch to your stride length.

Howdy ezrunner,

Thanks for using the Apple Support Communities.

If your Apple Watch did not track your distance properly, then I recommend following the calibration steps listed in the article below. This will help the Apple Watch learn your stride length and speed, and help increase its accuracy over time.

Calibrating your Apple Watch for improved Workout and Activity accuracy - Apple Support

Take care,

Alex H.