Area codes in Hamilton, Ontario
Hamilton, Ontario uses 4 area codes — 905, 289, 365 and 742. The main Hamilton area code is 905.
Area codes serving Hamilton
Phone numbers in Hamilton are written as ten digits — for example (905) 555-0190 — and fall in the Eastern Time zone.
How Hamilton came to have 4 area codes
The original Hamilton 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), 365 (2013) and 742 (2021). Existing numbers kept their original code — an overlay never forces anyone to change their number — which is why Hamilton now uses all 4 codes and every local call is dialed with ten digits.
All Ontario area codes · Is a Hamilton call a scam?
Nearby cities
- Oakville area codes
- Guelph area codes
- Brampton area codes
- Kitchener area codes
- Toronto area codes
- Buffalo area codes
- Oshawa area codes
- London area codes
More cities in Ontario
- Ottawa area codes
- Thunder Bay area codes
- Kingston area codes
- Windsor area codes
- Barrie area codes
- Sudbury area codes
Frequently asked questions
What is the area code for Hamilton?
The main area code for Hamilton, Ontario is 905. Hamilton is now served by 4 area codes in total: 905, 289, 365, 742.
How many area codes does Hamilton have?
Hamilton has 4 area codes: 905, 289, 365, 742.
Why does Hamilton have more than one area code?
As Hamilton 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 Hamilton number?
Dial all 10 digits — the area code (905 or 289 or 365 or 742) 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.