convert iphone 3gs to ipod

Hello Gwennol,

Thanks for asking the Apple Support Communities for help with converting you iPhone to an iPod for music.

You will need a SIM card to get through setup. Once you compete setup, you will be able to disable cellular, or remove the SIM card and return it to the device you borrowed it from. Remove or switch the SIM card in your iPhone or iPad - Apple Support

Then, activate and setup the device. These new articles may be slightly different than the older iPhone, but all you need to do is get through setup: Set up your iPhone, iPad, or iPod touch - Apple Support

Once you are set up:

1. Go to Settings > Cellular, and turn Celluar off
2. Keep Bluetooth and WiFi on
3. Turn the iPhone off and remove the SIM card or have insert a deactivated SIM card
4. Turn the iPhone back on and bingo your old iPhone now functions as an iPod touch!

This process uses the same Apple ID enabled on your device. To change Apple IDs, we suggest signing out of the current Apple ID and then erasing the device, then starting over. Thanks and have a wonderful day.