How to Obtain an IMSI
The International Mobile Subscriber Identity (IMSI) is used primarily as an identification number for each Android device. The IMSI associates a unique handset to its carrier, and retrieving the number can allow you to perform a system unlock on your device and track the phone if it has been stolen. There are three ways of obtaining your IMSI, which should only take several minutes to complete.
Type in *#06# and press "Enter" or "Call." A message should appear with your IMSI number.
Power down your cell device and remove the back plate and battery. Locate the IMSI number underneath the battery, which should be next to your device's serial number.
Locate your phone's identity page. Go to your menu screen and click "Settings." Consult your user's manual to find the exact location of the "Phone Status" or "About Phone" identity page. Once at the page, scroll down until you find the code labeled "IMSI."