Grimsby area codes
Grimsby, Ontario is served by 3 area codes: 289, 365 and 905. They overlay the same geography, so local calls take all ten digits regardless of which code a number uses. 289 carries the most numbers – 9 of the 16 number blocks assigned in the exchange, about 56%. The newest of them, 365, went into service in 2013. No single national carrier dominates: most blocks here are held by regional and competitive carriers.
Area codes serving Grimsby
Blocks are allocations recorded by the Canadian Numbering Administrator for this exchange area, not a count of people with those numbers.
Who holds Grimsby numbers
- Other38%
- VoIP providers19%
- Fibernetics13%
“VoIP providers” and “Other” group carriers whose names our mapping does not resolve individually – they are buckets, not companies.
Questions about Grimsby numbers
What area code is Grimsby?
Grimsby has 3: 289, 365, 905. All of them cover the same area, so a number can carry any of them.
Do I need to dial 10 digits in Grimsby?
Yes. Where two or more codes overlay the same area, every local call needs the full ten digits.
Which carrier has most Grimsby numbers?
Other holds about 38% of the number blocks assigned here. This is share of blocks allocated by the Canadian Numbering Administrator, not share of customers – people keep their numbers when they switch carriers.
Is 365 a new area code?
It went into service in 2013 as an overlay, meaning it was added to supply new numbers in the same area rather than replacing the existing codes.
Is a call from a Grimsby number safe?
The area code tells you nothing about that. Spam callers routinely fake the number they display, often choosing a local-looking one because it gets answered more often. Look up the full number instead.
Other places in Ontario
Source
Canadian Numbering Administrator, CO Code Status, data date 31 October 2026. The CNA publishes one file per area code each weeknight; we aggregate by exchange area and province.
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