Area codes in Oakville, Ontario
Oakville, Ontario uses 3 area codes — 905, 289 and 365. The main Oakville area code is 905.
Area codes serving Oakville
Phone numbers in Oakville are written as ten digits — for example (905) 555-0190 — and fall in the Eastern Time zone.
How Oakville came to have 3 area codes
The original Oakville area code is 905, in service since 1993. As the area ran low on available numbers, overlay codes were added over the same region for new phone lines: 289 (2001) and 365 (2013). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why Oakville now uses all 3 codes and every local call is dialed with ten digits.
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Nearby cities
- Hamilton area codes
- Brampton area codes
- Toronto area codes
- Guelph area codes
- Kitchener area codes
- Oshawa area codes
- Buffalo area codes
- Barrie area codes
More cities in Ontario
- Ottawa area codes
- London area codes
- Thunder Bay area codes
- Kingston area codes
- Windsor area codes
- Sudbury area codes
Frequently asked questions
What is the area code for Oakville?
The main area code for Oakville, Ontario is 905. Oakville is now served by 3 area codes in total: 905, 289, 365.
How many area codes does Oakville have?
Oakville has 3 area codes: 905, 289, 365.
Why does Oakville have more than one area code?
As Oakville used up the numbers available in its original area code (905, in service since 1993), additional "overlay" codes were added over the same area so new phone numbers could keep being assigned.
How do you dial a Oakville number?
Dial all 10 digits — the area code (905 or 289 or 365) followed by the 7-digit local number. From abroad, dial +1, then the area code and number.
Sourced from the official NANPA (North American Numbering Plan Administrator) numbering database, current as of August 2, 2026. Refreshed monthly.