All Openfit Live classes require a reliable internet connection - WiFi or Cellular - to stream the trainer's voice, music, demo videos, and workout stats.
For best app performance during any outdoor Openfit Live classes, ensure that you have a strong cellular data signal (EDGE, 3G, LTE) wherever you are exercising.
You can use WiFi for any indoor Openfit Live workouts, and no cellular data is necessary.
However, to get the most out of Openfit Live and take advantage of all the classes available, you will need a cellular data plan.
If you want to save a bit of data, you can join the class a few minutes before it starts (you'll go into the 'warmup room'), and use your home WiFi to buffer the music. The music will download in the background, and will be ready to play when the class begins. When the class is about to begin, just switch your WiFi off and head outside!