Yes, Granite Telecommunications allows customers to keep their existing phone numbers through a process known as number portability. This means that when switching to Granite, customers can transfer their current phone numbers to their new service without any issues. However, it is essential to ensure that you do not cancel your current service before the number has been successfully transferred, as this could lead to complications. To facilitate this process, it is advisable to have your account information from your previous provider available when initiating the transfer with Granite. Additionally, factors such as account status and the type of service may impact the portability of certain numbers. For more detailed information on number portability and the necessary steps, it can be helpful to refer to the current web page of Granite Telecommunications.