This page connects featured cities in Ontario with their published or clearly qualified telephone numbering associations.
“Largest” refers to the priority city set used by this directory. It is not a live population ranking.
| City | Domestic area code | International prefix | Context |
|---|---|---|---|
| Toronto | 416, 647 | +1 416, +1 647 | Toronto’s full current overlay complex is 416, 437, 647 and 942; this launch links two priority code pages. |
| Ottawa | 613, 343 | +1 613, +1 343 | Ottawa’s current overlay complex is 343, 613 and 753. |
| Mississauga | 905, 289 | +1 905, +1 289 | Mississauga is in the 289, 365, 742 and 905 Southern Ontario overlay complex. |
| Brampton | 905, 289 | +1 905, +1 289 | Brampton is in the 289, 365, 742 and 905 Southern Ontario overlay complex. |
| Hamilton | 905, 289 | +1 905, +1 289 | Hamilton is in the 289, 365, 742 and 905 Southern Ontario overlay complex. |
| London | 519 | +1 519 | London, Ontario is in the 226, 382, 519 and 548 overlay complex. |
| Markham | 905, 289 | +1 905, +1 289 | Markham is in the 289, 365, 742 and 905 Southern Ontario overlay complex. |
| Vaughan | 905, 289 | +1 905, +1 289 | Vaughan is in the 289, 365, 742 and 905 Southern Ontario overlay complex. |
| Kitchener | 519 | +1 519 | Kitchener is in the 226, 382, 519 and 548 Southwestern Ontario overlay complex. |
Dial the complete ten-digit Canadian number in the featured overlay regions. Use +1 once in international format; a domestic long-distance 1, where required, is an access prefix rather than an additional part of the number.
Canada spans Newfoundland, Atlantic, Eastern, Central, Mountain and Pacific time zones, with regional exceptions
America/Toronto: Calculated in your browser
Area codes identify numbering-plan areas, not a phone’s exact or current location. Wireless service, VoIP and number portability can separate a number from the subscriber’s physical location. Most populated Canadian regions now have several overlay codes with identical coverage, so ten-digit local dialling is required.
A code listed beside a city reflects a featured numbering association; it does not assert that every community in Ontario uses that code or that the code stops at the administrative border.
This release includes 7 verified or clearly qualified code associations for the featured cities in Ontario.