About 905:
Area code 905 was first put in service October 4, 1993. In 2001, area code 289 was created as an overlay to area code 905. In 2013, area code 365 was created as an overlay to area code 905. Currently, the largest city it serves is Hamilton, ON, and it overlaps coverage areas with area codes 289 and 365.
Related Cities:
Area codes 905, 289 and 365 cover a portion of southern Ontario including Niagara Falls and the Greater Toronto Area, and the larger communities of Ajax, Ancaster, Aurora, Brampton, Burlington, Caledon, Cobourg, Dunnville, Fort Erie, Georgetown, Hamilton, King Township, Maple, Markham, Milton, Mississauga, Newmarket, Oshawa, Richmond Hill, St. Catharines, Stoney Creek, Thornhill, Unionville, Welland, Woodbridge and many smaller surrounding communities in the area codes 905 and 289 overlay service area.