Number porting is the process of moving a telephone number from one communications provider (CP) to another. The process may incur a fee, depending on the CP you're moving from and the one you join. If customers are used to reaching you through your current number, you may not wish to establish a new one.
What happens when you port your number?
Porting is generally a permanent means of moving a phone number to another provider, as the old account associated with the number will be closed. Compare this to forwarding, where the number keeps its old account association, but is forwarding to another number or person instead.
How does porting a phone number work?
Send the following text message - PORT followed by your 10-digit mobile number to TRAI's central number for mobile number portability - 1900. Example: Send 'PORT 98xxxxxx98' to 1900. You'll receive an SMS back with a port out code which will remain valid for only 15 days.