To port to MTN, you first need to purchase an MTN SIM card and RICA it. Next, using your current SIM, SMS ’PORTME#’ followed by your 10-digit MTN SIM number’ to 083 767 8287. An example SMS: PORTME#0000000000.
You will then receive an SMS on your current SIM indicating that the porting process is underway. The last step is to insert your new MTN SIM into your phone the following day and select “new number” to activate it.
According to the MTN website, you will lose airtime and data on your current SIM when you port, so make sure to use them up before porting.