How to Disconnect From Cellular Data on an iPhone
- 1). Press the "Home" button on the iPhone. Tap "General."
- 2). Tap "Network" to access the settings for cellular data on your iPhone.
- 3). Tap the field next to "Cellular Data" to switch it to "Off" and disconnect from it.
- 4). Press the "Home" button to exit to the iPhone's home screen.
Source...