If you need to find out your iPhone's carrier without a SIM card installed, you can do so through the Settings app.

To unlock your iPhone from its carrier, you'll likely need to contact your carrier directly to cancel your contract.

No one likes dropping offline, especially if you need to stay in contact. Get expert tips for boosting your cellphone signal on iPhone or Android.

If you've ever called your carrier's customer service to activate a prepaid SIM card or troubleshoot a malfunctioning Android SIM card or iPhone SIM, then you've likely needed your ICCID number. The ...