Area code 905 — Ontario
Greater Toronto Area suburbs and Niagara. Relief assignment, in service since 1993.
At a glance
- Country
- Canada
- Province / territory
- Ontario
- Service area
- Greater Toronto Area suburbs and Niagara
- Time zone
- Eastern Time (EST/EDT, UTC-5/-4) · current offset -04:00
- Type
- Relief
- In service since
- 1993
- Country code
- +1 (NANP)
Map
Cities served by 905
Related & overlay area codes
Area code 905 shares geography with 3 other codes serving the same region. A call placed inside this overlay must dial all 10 digits regardless of which code your own line uses.
Carriers operating in 905
The following national and regional telecommunications carriers hold central office (CO) code assignments within numbering plan area 905. Number portability means a phone number originally issued by one carrier may now ride on another carrier's network.
About area code 905
Area code 905 is a Canadian numbering plan area covering Greater Toronto Area suburbs and Niagara. It was placed into service in 1993 as a relief code, and today operates under the Eastern Time (EST/EDT, UTC-5/-4) time zone.
Numbers in the 905 NPA are issued in central office (CO) blocks of 10,000 to local exchange carriers, who then assign them to subscribers. Because Canada uses a competitive carrier model under CRTC oversight, multiple carriers — both incumbent and competitive — hold blocks within 905. The current carrier of record for any specific number can be looked up via the Canadian Local Number Portability Consortium, but the originally issued carrier is no longer a reliable signal of who actually serves that line.
If you receive a call from a number beginning with 905, the caller is either physically located in or has historically been associated with Greater Toronto Area suburbs and Niagara. The same applies to overlay codes 289, 365, 742: any of these area codes can correspond to a phone in the same geography, and many households carry numbers from two or three different overlays simultaneously across landlines and mobile devices.
To call a number in 905 from outside Canada and the United States, dial your country's international access prefix, then +1 905 followed by the 7-digit local number. Within the NANP, simply dial 1 followed by all 10 digits — or just the 10 digits if you are also located in an overlay region where 7-digit local dialling is no longer permitted.
Frequently asked questions
Where is area code 905?
Area code 905 serves Greater Toronto Area suburbs and Niagara in Ontario, Canada.
What time zone is 905?
Numbers in 905 are in the Eastern Time (EST/EDT, UTC-5/-4) time zone.
Is 905 a toll-free or mobile-only code?
No. Canadian area codes are geographic — they apply to both landline and mobile numbers in Greater Toronto Area suburbs and Niagara. Toll-free codes in the NANP (800, 833, 844, 855, 866, 877, 888) are a separate category.
Why do I see calls from 905 if I do not know anyone there?
Two reasons. First, mobile portability: someone who moved away from Ontario can keep their 905 number anywhere in the world. Second, scam callers frequently spoof Canadian area codes to appear local. If you do not recognise the number, it is generally safe to let it go to voicemail.