The Canadian Wireless Code of Conduct guarantees consumers the right to retain their old number when switching to a new plan with the same or different cell phone carrier. The process involved is called ‘port forwarding.’ During this process, it is essential to not cancel your old plan before you have successfully transferred your number to a new plan, otherwise, your old number will go back into circulation.  Many carriers offer this as an option when signing up for a new plan online – just look for the ‘port forward’ option on their website. When the new SIM arrives, go online and login to your self-service account and activate the sim card in order to initiate the transfer. You will normally receive a text message from your old carrier looking for verification that you do want to move your number to a new carrier. Once this message is accepted, the transfer process should commence. As soon as your old SIM stops working and you insert the new one, the transfer should be complete, and your old plan cancelled.  For more information about how each carrier allows for ‘port forwarding’ options, it is always helpful to review each carrier’s dedicated FAQ page which provides more specific information.