How Do I Stop My iPhone From Going Into Roaming?by Alexis Rohlin
You may notice your iPhone goes into roaming when you travel away from home and during trips out of the country. This is because the iPhone's normal carrier, AT&T, has a weak signal in the area and your iPhone has to look for and use a different service provider's cell tower. Roaming means that your iPhone is using another network for a short period. Even though you are being billed by your existing phone provider, you are charged a higher rate for using a different phone service.
Data roaming fees on your iPhone bill can be quite high, and it is in your best interest to turn off the data roaming on your iPhone when you notice that it is roaming to prevent a huge phone bill.
Enable Airplane Mode
Enable the airplane mode on your iPhone to prevent it from roaming. This also turns off the radio, Wi-Fi and GPS. Go to the "Settings" screen on your iPhone. Tap "Settings." Tap the slider bar of "Airplane Mode" to "On" to enable it.
Wi-Fi Only Setting
You won't be billed for downloading or browsing with your iPhone's Wi-Fi connection. Only browse or go on the Internet on your iPhone when you are in an area that provides free Wi-Fi. To only use your Wi-Fi, enable "Airplane Mode." Tap "Settings." Tap Wi-fi" and turn on the Wi-Fi and select a Wi-Fi network that is available in your area.
Turn Data Roaming Off
Tap "Settings." Tap "General." Select "Network" by tapping on it. Tap "Data Roaming." Tap "Turn off Data Roaming." Your iPhone will no longer roam.