How to Disable Wi-Fi on an iPhone 4by Kefa Olang
The Wi-Fi feature on your iPhone 4 allows you to connect to wireless acess points for blazing data transfers; however, you may need to disable it if you are on a plane or when troubleshooting some network connection problems. Once disabled, your iPhone connects to the Internet via your cellular data network. Turning off the Wi-Fi feature on your iPhone 4 is simpler than it looks. The best part of it is that you can reactivate the wireless feature whenever you choose to.
Press the "Home" button on your phone and drag the slider to the "Unlock" position. This displays the home screen.
Tap the "Settings" icon to launch your iPhone 4's settings.
Tap "Wi-Fi" to launch the Wi-Fi Networks screen. Tap the "ON" button. It automatically changes to "OFF."
Press the "Home" button to return to the home screen. Wi-Fi is disabled.