IMEI and ESN Basics Guide
What IMEI and ESN numbers represent, where to find them on any device, when to use each, and the common situations where dealers verify them.
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What this IMEI and ESN Basics Guide helps you do
IMEI and ESN numbers run through nearly every wireless transaction - activations, unlocks, trade-ins, insurance claims, and blacklist checks. This free guide explains what each number actually represents, where to find them on different devices, when to use IMEI versus ESN, and the most common situations where dealers need to read or verify these numbers correctly. Foundational reference for any wireless retail employee who touches activations, trade-ins, or device checks.
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IMEI and ESN Basics FAQ's
What is an IMEI number?
IMEI stands for International Mobile Equipment Identity - a unique number that identifies a specific cellular device. It is used in activations, unlocks, trade-ins, insurance claims, and blacklist or blocklist checks. You can usually find it by dialing star-pound-zero-six-pound, or in the phone's settings, on the SIM tray, or on the original box.
Both identify a device, but IMEI is used on GSM and modern networks, while ESN (Electronic Serial Number) and its successor MEID were used primarily on older CDMA devices. Today the IMEI is the number you will use in the vast majority of transactions, but you may still encounter ESN or MEID references on older equipment.
What is the difference between IMEI and ESN?
How do I check if a device is blacklisted?
A blacklist or blocklist check uses the device's IMEI to see whether it has been reported lost, stolen, or unpaid. A blacklisted device generally cannot be activated. Always verify the IMEI status on a used or trade-in device before accepting it, since a blacklisted phone has little resale value and cannot be put back into service.
Where do I find the IMEI on a phone?
The fastest way is to dial star-pound-zero-six-pound on the device, which displays the IMEI on screen. You can also find it in the phone's settings under About, on the physical SIM tray on many phones, or printed on the original packaging. For trade-ins, confirm the on-screen IMEI matches the box.