The 905 and 289 telephone area codes, which include the Hamilton region, will soon be joined by a new one: 365.

The new code will start to roll out March 25, once there are no more 905 or 289 numbers left. Each area code can cover about 7.5 million unique phone numbers.

"These new area codes reflect the growing use of cellphones and other mobile devices. Telecommunications service providers will be able to accommodate the growing demand for new telephone numbers with absolutely no impact on customers," said  Glenn Pilley, director of the Canadian Numbering Administrator, in a release. 

The phone numbers of those who already have a 905 or 289 area code will stay the same. But new lines or cellphones will get the 365 code.

"We expect the first numbers with the new area codes to be assigned over the coming months as part of a seamless transition process," Pilley said.

The 905 and 289 area codes cover Ajax-Pickering, Brampton, Burlington, Hamilton, Markham, Milton, Mississauga, Oakville, Oshawa, Richmond Hill, St. Catharines and Whitby.

Down the road in Toronto, the areas covered by the 416 and 647 codes will be getting a third area code as well: 437.

New area codes will also be introduced in the coming months in other regions throughout Canada including Manitoba, Saskatchewan, British Columbia, Nova Scotia and Prince Edward Island.