How your outgoing call is charged depends on where you’re physically located when you place the call, regardless of your phone number. The cell site that picks up your call determines the local calling area.
For example, if you have a Toronto number (e.g. 416-xxx-xxxx) but are picked up by a Calgary cell site, you can call anyone in the Calgary local calling area and not be charged long distance.
: If you make an outgoing call to a number within your local calling area, and then travel out of your area without disconnecting the call, the entire call will be billed as a local call.