Area code 905 (1-905) (with overlay Area code 289) is a telephone dialling area for southcentral Ontario. It includes the Niagara Peninsula, Hamilton, west suburban Toronto, the northern suburbs, and the eastern suburbs.

It was first assigned in Canada in October of 1993 out of area code 416. 905 overlays with area code 289. It surrounds area code 416/647 (the city of Toronto) and is bounded with Area code 519 in the west, Area code 705 in the north and Area code 613 in the east. All numbers, after 2002, must be dialled with an area code, changing the number of digits for local telephone numbers from 7 to 10.

The 905 area has become a label for the fast growing suburban areas around Toronto and is recognized as one of the most important political regions in Canada.

• Area:

• 905-509
• Concord: 905-669
• Maple: 905-832
• Newmarket: 905-853
• Woodbridge: 905, -264-5, -850-1-6

A previous version of the +1-905 area code was once used as a block of alternate numbers for calls from the United States to Mexico (+52-5-...) in the days when overseas calls otherwise would have needed to be placed through a telephone operator. This use became obsolete with the widespread introduction of direct dial overseas calls and was completely abolished no later than 1991.

See also

• List of North American area codes