This article explains how to find out if your iPhone is unlocked and not tied to a single carrier. Methods include checking the iPhone settings, using a new SIM card, and using an IMEI service.
How to Check if an iPhone is Unlocked! (2021)
The easiest way to see if your iPhone is unlocked is to check your Settings menu. This method isn’t always accurate, but it’s a good place to start.
Open the Settings app on your iPhone.
Tap Cellular > Cellular Data Options.
