Area code 365: Ontario
Area code 365 is a Canadian province area code for Ontario, on Eastern Time. It has 706 prefixes in service across 88 exchange areas, the largest being Markham, Hamilton and Brampton. It shares its area with 289, 742 and 905, so local numbers there can start with any of them. Local calls there take 10 digits.
Local time in area code 365
America/Toronto
Prefixes in service
706 of 792 possible
88 exchange areas
Area code 365 facts
| Location | Ontario, Canada |
|---|---|
| Time zone | Eastern Time |
| Overlays | 289, 742, 905 |
| Overlay of | 905 |
| In service since | March 25, 2013 |
| Local calls | 10 digits; toll calls 1 + 10 digits |
| Carrier | Not shown. An area code is where a number was issued; numbers port between carriers. Check line type |
Which cities and towns use area code 365?
The Canadian Numbering Administrator records each prefix against an exchange area, usually named after its main town. These are the 365 exchange areas with the most prefixes in service. 76 smaller ones aren't listed.
| Exchange area | Prefixes |
|---|---|
| Markham | 51 |
| Hamilton | 48 |
| Brampton | 27 |
| Thornhill | 24 |
| Oshawa | 23 |
| Ajax-Pickering | 21 |
| Aurora | 20 |
| Oakville | 17 |
| St. Catharines-Thorold | 15 |
| Newmarket | 13 |
| Burlington | 12 |
| Dunnville | 11 |
Source: Canadian Numbering Administrator CO code status, file dated 2026-10-16. Each prefix holds up to 10,000 numbers.
How do I dial a 365 number?
NANPA's dialling plan for 365: local calls inside the code take 10 digits, toll calls 1 + 10 digits. From another area code, dial 1 first. From abroad, use +1. The examples use 555-0147, from a range reserved for fictional numbers.
| Local call inside 365 | 365-555-0147 |
|---|---|
| From another US or Canadian area code | 1-365-555-0147 |
| From outside North America | +1 365 555 0147 |
| E.164, for CRMs and SMS tools | +13655550147 |
When did area code 365 start?
Area code 365 went into service on March 25, 2013 as an overlay of 905. Today 365, 289, 742 and 905 cover the same area as an overlay, which is why 10-digit dialling is needed for local calls there.
Tools for 365 numbers
- Area code lookup
Look up any code or a whole list of numbers, or find the codes for a state or city.
- Area code time zone
Local time for a list of numbers, with a callable-now flag.
- NPA-NXX lookup
Rate center and state for one prefix, a level below the area code.
- TCPA calling hours checker
Whether it's inside the federal 8 a.m. to 9 p.m. calling window there now.
Next step
A 365 number tells you where it was issued, not what it is now.
Mobiles, landlines and VoIP lines share area codes, and numbers move between carriers. A live line-type and carrier lookup on every number in your list says which is which, and that decides which calling and texting rules apply. It's in the Email + Phone plan.
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Area code 365 questions
- What province is area code 365?
- Area code 365 is in Ontario, Canada. Its largest exchange areas by number of prefixes are Markham, Hamilton, Brampton, Thornhill and Oshawa.
- What time zone is area code 365 in?
- Eastern Time.
- What area codes overlay 365?
- 289, 742 and 905. An overlay adds a new code to the same area instead of splitting it, so neighbours can have different area codes and local calls need 10 digits.
- When did area code 365 start?
- Area code 365 went into service on March 25, 2013 as an overlay of 905.
- Is a 365 number a cell phone or a landline?
- The area code can't tell you. In the US and Canada mobiles, landlines and VoIP lines share area codes and prefixes, and numbers move between carriers and line types. Only a live line-type lookup answers it for one number.
- How many phone numbers does area code 365 have?
- 706 of its 792 possible prefixes are in service, and each prefix holds up to 10,000 numbers. That counts prefixes assigned to carriers, not numbers in use.
Other area codes in Ontario
Sources
Location, overlays, in-service date and dialling plan: NANPA NPA database, file dated 10/16/2026. Prefixes and exchange areas: Canadian Numbering Administrator CO code status, 2026-10-16. Time zones mapped to the IANA time zone database. By the SimpleVerifier Team; how we build these pages.