Yes, the Uber app relies heavily on your phone's cellular data to function, as it requires a constant, real-time connection to Uber’s servers to coordinate rides. Specifically, it uses data for GPS tracking, which allows both you and the driver to see each other's locations on a live map. It also uses data to process payments, send push notifications about your driver's arrival, and facilitate in-app messaging or VOIP calls between you and the driver. While a single ride doesn't consume a massive amount of data (typically a few megabytes), keeping the app open for long periods can add up. Furthermore, Uber often collects "background data" if your settings allow it, which helps the company improve pickup accuracy and estimate traffic patterns. If you are traveling internationally or have a limited data plan, it is a good idea to connect to airport or hotel Wi-Fi to book the ride, though you will still need an active data connection once you leave the Wi-Fi range to track your car's progress.