TORONTO, Ont. – Two new area codes have come into effect in the GTA, Monday.

The 437 area code will be added to the 416 and 647 areas, while people who live in the 905 and 289 region will have a new 365 area code.

The 416/647 area codes are used in Toronto, while the 905/289 area codes cover southern Ontario, including Ajax-Pickering, Brampton, Burlington, Hamilton, Markham, Milton, Mississauga, Oakville, Oshawa, Richmond Hill, St. Catharines and Whitby.

The Telecommunications Alliance says that in addition to population growth, the new area codes reflect the growing use of cell phones and mobile devices.

However, if you sign up for a new number, you may still get one of the older area codes for the next few months until the numbers run out.