Since launch the Apple Watch has always required a permanent connection to an iPhone to function properly, expect from being an actual watch and using Apple Pay. Now with the recent launch of watchOS 2 the Apple Watch can run native apps and execute the code on device without the need for the iPhone to be connected. This also allows the watch to be a true fitness device as apps such as Runkeeper, which has been recently updated to support native applications on the Apple Watch.
It’s a pretty simple process to get a run started, just open the app, tap run, cycle or other and get going. The Apple Watch will then track the time, distance and how long you took to run a mile. One downside is that it won’t be able to track GPS data without the iPhone being connected, if this doesn’t bother you then you can leave your phone behind – but every run won’t have the benefit of GPS data.