To disable data roaming on your phone:

1. Check your service plan: Consult with your mobile service provider to determine whether you are currently subscribed for data roaming. If you are not, no further action is necessary.
2. Configure your phone's settings:
   1. On the phone's home screen, access the Settings menu.
   2. From the Settings menu, select Mobile Data.
   3. Look for Roaming and select Data Roaming.
   4. Switch the Data Roaming toggle off.