Aside from your device’s IMEI, you can also check your device’s carrier using the ICCID if for some reason the carrier information is not available.
Each iPhone or any device is unique because it has its own IMEI number, serial number and more recently it can also be tied to an ICCID number (you can find all these under Settings, General, About). ICCID is the short form for Integrated Circuit Card ID.
If you have no access to your iPhone’s About screen especially if your iPhone is stuck on the activation screen after doing a full restore, you can also get the ICCID/IMEI number by using iTunes. Simply plug in your iPhone to your computer and you’ll see a display that shows all sorts of information about your device.
Click on the phone number and you will get the IMEI and ICCID. iTunes will store the IMEI and ICCID of every device that has been synced with iTunes before. By using this free ICCID carrier checker, it will return the carrier information after entering your device ICCID.
How useful is the ICCID number? A good example would be if your iPhone has gone missing or stolen. If the person who has your iPhone and he or she inserted a different SIM card, your iPhone will store the SIM card’s ICCID on that device. If it’s synced on iTunes, the ICCID will be stored on Apple’s database and therefore making it possible for you to track your stolen iPhone. Read more on the blog post I wrote earlier this year: It’s Possible to Track Your Stolen or Missing iPhone with its ICCID and CTN.
Technically this free ICCID carrier checker should also work for non-iPhone devices although I’m not entirely sure how to get your device ICCID on Android or Windows Phones.