The internet connection on smartphones may remain online permanently and interfere with the working of the mobile telephony device. Some users do not have any internet package or plans activated for accessing the internet from their smartphone, and may therefore wish to disable the internet connection on the smartphone. This can be done by disabling the APN settings of the ISP in the phone. For Android phones, the APNdroid can be used to disconnect the internet. For Windows Mobile or Symbian phones, the Nodata software may be used to disable the internet connection on the smartphone. All the software can be downloaded for free from the internet. 

Disable the Internet connection on your smartphone

• Disable Internet Connection on your Android phone
• Disable the Internet connection on Windows Mobile or Symbian
• See also: How to block internet on android phone

Most of the latest PDAs are permanently connected to the Internet, in order to perform updates. This poses problems to users that don't have any Internet package or who are using prepaid accounts.

• To manage the connection, there are applications to disable the APN (Access PointName) settings of your ISP

Disable Internet Connection on your Android phone

• (1) Go to "Settings", then "wireless network" and click on "mobile". Just uncheck "Data enabled" so that your phone will not connect over the data network. Note that you will be unable to send or receive MMS when this option is unchecked.
• (2) You can use Data Enabler. This small widget can cut the connection to the data network quickly.*From your phone go to Android Market and search for "APNdroid", or download it directly at:http://code.google.com/p/apndroid/
• (3) Open software, press the On/Off to activate/deactivate the Edge/3G/GPRS connection modes. This will not disable the use of MMS or WiFi on the phone.

Disable the Internet connection on Windows Mobile or Symbian

You can download the "nodata" software: here 

Thanks to Gouby for this tip