This guide will show you step by step how to disable 3G on your iPhone, or any iOS device. If you are disabling 3G to help increase battery I would recommend our guide on how to increase iPhone battery life. In my experience disabling 3G will save loads of battery but it makes your iPhone dog slow for any Internet use, handy if you are away from a power source and your phone drops to 20% battery or less…
- Unlock your iPhone
- Tap Settings
- Tap General

- Click on Network

- Turn off 3g by sliding Enable 3G to the off position.OK

- Press the home button
