User level: Level 1 (4 points)How can I find out which US SIM carrier my iPhone 12 belongs to using its IMEI or serial number?
Posted on Sep 16, 2026 8:17 AM
User level: Level 10 (454,138 points)Sep 16, 2026 8:24 AM in response to farshi64
On an iPhone, you generally cannot determine with certainty which mobile carrier originally supplied or activated the device simply by looking at the iPhone or its settings. Unless the original owner or seller tells you which carrier the iPhone was associated with, that historical carrier information is not normally available to you.
This becomes particularly important when you are trying to determine whether an iPhone is carrier-locked. Knowing that an iPhone is locked is one thing; identifying which carrier has imposed the lock can be much more difficult without information from the original purchaser or the carrier.
Apple's user-facing documentation and iPhone settings do not normally provide a complete historical record showing every carrier that has previously been used with the device. Carrier-lock status is tied to the carrier's activation and unlocking systems, so the relevant information is maintained by the carrier rather than exposed as a complete history to the device owner.
You can check the iPhone's current lock status under Settings → General → About → Carrier Lock. If it says “No SIM restrictions,” the iPhone is unlocked. If it indicates a SIM restriction, the device is carrier-locked, but the iPhone itself may not tell you which carrier originally placed that restriction.
Therefore, when buying a used or imported iPhone, knowing its original carrier and country of sale can be extremely important. If the seller cannot provide that information, determining the exact carrier responsible for a lock may be difficult or, in some cases, practically impossible without contacting carriers or using their device-checking systems.
In short: the iPhone can tell you whether it is currently carrier-locked, but it does not normally give you a complete historical record of which carrier previously used or locked the device. The original seller is often the most reliable source for that information.
User level: Level 10 (756,437 points)Sep 16, 2026 8:21 AM in response to farshi64
Choose Settings, General, and About, and look at the Carrier Lock line. If you can't use that method, click here and contact Apple Support.
(264962)
User level: Level 7 (28,946 points)Sep 16, 2026 8:25 AM in response to farshi64
Why don't you know what carrier you are using and paying for? Try this...
Settings->General->About->scroll down to Network. My iPhone says AT&T
Originally posted at discussions.apple.com/thread/256358257