If you want to place calls but not use data: Turn Data Roaming "OFF".
By default, the setting for international data roaming will be in the "OFF" position. Turning "OFF" data roaming blocks email, browsing, visual voicemail and downloads, but it will not block text or picture/video messages.
To turn data roaming "ON/OFF", tap on
Settings>General>Network>Data Roaming
When abroad, international roaming rates apply when you send text or picture/video messages.
To access audible voicemail when data roaming is "OFF": tap on
Phone>Voicemail (International roaming voice rates apply.)
Utilize Wi-Fi instead of 3G/GPRS/EDGE -
Wi-Fi is available in many international airports, hotels and restaurants to browse the Web or check email.
If you want to use data but not receive email automatically:
Turn Fetch New Data "OFF" - Check email and sync contacts and calendars manually instead of having the data pushed to your iPhone automatically.
This way you can control the flow of data coming to your iPhone.
To turn off the Auto-Check functionality tap on
Settings>Mail, Contacts, Calendars>
Fetch New Data, Change Push to "OFF" and select option Fetch Manually
Utilize Wi-Fi instead of 3G/GPRS/EDGE to download and manually check email:
Wi-Fi is available in many international airports, hotels and restaurants.
International Plans / roaming
To add an international data package:
call 1-800-331-0500.
Reset the usage tracker to zero -
When you arrive overseas, access the usage tracker in the general settings menu and select reset statistics. This will enable you to track your estimated data usage while abroad.
To reset Usage Tracker to Zero tap on
Settings>General>Usage>Reset Statistics