To transfer old contacts from a subscriber identity module (SIM) that was in an older mobile phone to your iPhone, insert the SIM card into your iPhone and import the contacts from within your iPhone's settings. Many mobile phones are designed to store names, phone numbers and contacts on their SIM cards. An iPhone requires a SIM for operation, but the iPhone does not store any actual data on the SIM.
Turn off your iPhone. Hold the power button until you see a notice on the display advising you to slide to power it off. Slide the image on the iPhone's touchscreen and it will power off after a few seconds. Many people do not realise that tapping the power button only turns off the display.
Remove the SIM tray from your iPhone. Look on the top edge of the phone for a tiny hole, which is just wider than a paper clip. Insert a paper clip into the pinhole, and the SIM tray will eject.
Set aside the iPhone's SIM from the tray and insert your old SIM. One corner of a SIM card is flattened to make alignment easier.
Insert the SIM tray into the iPhone and power it back on. If you have one, enter your unlock code once it is on.
Open the Settings application on your iPhone by tapping on it.
Select the "Mail, Contacts, Calendars" menu from your phone's settings. You may need to scroll down to see the "Import SIM Contacts" menu. Once you tap on that, your phone will begin to import the data stored on the old SIM. This data should include your contacts.
Turn off your iPhone once the import completes, then swap the SIMs back to their original configuration. Your iPhone will have no service until you replace the SIM you removed earlier.
The pinhole in an iPhone SIM is always on the edge closest to the headphone jack.
Always hold a SIM card by the edges. The exposed metal contacts on the card can malfunction if you get debris or fingerprints on them.