The Telecommunications Alliance says high demand means a new area code for southwestern Ontario starting in June 2016.
The 548 area code is being added for the region currently covered by the 519 and 226 area codes.
That includes the area from Windsor in the west, to Guelph in the east and Owen Sound in the north, encompassing London, Sarnia, Woodstock, Kitchener-Waterloo, Stratford and Brantford.
The new number won't impact existing numbers and will be introduced as new numbers are issued.
In a statement, Glen Brown, spokesperson for the Canadian Numbering Administrator, said, "Telecommunications service providers will be able to accommodate the growing demand for new telephone numbers with no impact on consumers and businesses...[it] demonstrates the flexibility and growth potential of Canadian communications networks.”
After June 4, 2016, residents or businesses asking for a new phone number could get a 519, 226 or 548 area code.
