How to Check Locked/Unlocked Status on iPhone
On iOS 14 and above, open Settings,
Scroll down and tap on General, then select About.
If you see the No SIM Restrictions message next to Carrier Lock, then your iPhone is unlocked.
Is My Android Phone Locked?
Unfortunately, Android doesn’t have an option to check SIM restrictions in the settings as newer iPhones do, but that doesn’t mean you’re entirely out of luck.
How to Check Locked/Unlocked Status on Android
Access Settings from the drop-down menu or through your App Drawer.
Tap on Connections, Network & Internet, or other variations depending on brand and model.
Select Mobile network, Cellular network, or other variation depending on brand and model.
Tap on Advanced (if needed) and select Choose Network, Automatically select network, or another variant to open the list of carriers.
If several carriers appear, the chances are that your phone is unlocked and just needs the appropriate SIM card. For further confirmation, continue to Step 6.
Remove the old SIM card from your phone and insert the newly activated one from the other carrier. Try using mobile data to browse the internet but ensure that Wi-Fi is disabled.
If you successfully browsed the internet, your phone is definitely unlocked.