Area code 343: Ontario
What is area code 343?
Area code 343 is a Canadian province area code for Ontario, on Eastern Time. It has 641 prefixes in service across 116 exchange areas, the largest being Ottawa-Hull, Kingston and Cornwall. It shares its area with 613 and 753, so local numbers there can start with any of them. Local calls there take 10 digits.
Free, runs in your browser; nothing is sent. The sample is a sample, not a real line.
Paste your 343 numbers (a mixed list is fine). They are counted here at once; the free checker then gives every number its E.164 form, country and line type, with a file to download.
By continuing you agree to our Terms and Privacy Policy.
Need the current carrier and real line type of each number?
See the phone add-onArea code 343 facts
| Location | Ontario, Canada |
|---|---|
| Time zone | Eastern Time |
| Overlays | 613, 753 |
| Overlay of | 613 |
| In service since | May 17, 2010 |
| 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 |
In short: 343 is Ontario (Eastern Time). Format checks here are free and run in your browser; the current carrier and line type need a live lookup. Bulk phone number validator · Pro + Phone plan
Local time in area code 343
America/Toronto
Prefixes in service
641 of 792 possible
116 exchange areas
Which cities and towns use area code 343?
The Canadian Numbering Administrator records each prefix against an exchange area, usually named after its main town. These are the 343 exchange areas with the most prefixes in service. 104 smaller ones aren't listed.
| Exchange area | Prefixes |
|---|---|
| Ottawa-Hull | 104 |
| Kingston | 23 |
| Cornwall | 22 |
| Belleville | 19 |
| Brockville | 17 |
| Bancroft | 13 |
| Kanata-Stittsville | 12 |
| Jockvale | 10 |
| Merrickville | 10 |
| Carleton Place | 9 |
| Smiths Falls | 9 |
| Hawkesbury | 8 |
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 343 number?
NANPA's dialling plan for 343: 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 343 | 343-555-0147 |
|---|---|
| From another US or Canadian area code | 1-343-555-0147 |
| From outside North America | +1 343 555 0147 |
| E.164, for CRMs and SMS tools | +13435550147 |
When did area code 343 start?
Area code 343 went into service on May 17, 2010 as an overlay of 613. Today 343, 613 and 753 cover the same area as an overlay, which is why 10-digit dialling is needed for local calls there.
Tools for 343 numbers
- Bulk phone number validator
Format, country and number type for every number in a CSV, with E.164 output.
- 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 343 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 phone add-on.
No list right now? This tool stays free, no account, so bookmark it for next time. Ctrl+D (⌘+D on a Mac)
Ready to verify now? See the phone add-on
Area code 343 questions
- What province is area code 343?
- Area code 343 is in Ontario, Canada. Its largest exchange areas by number of prefixes are Ottawa-Hull, Kingston, Cornwall, Belleville and Brockville.
- What time zone is area code 343 in?
- Eastern Time.
- What area codes overlay 343?
- 613 and 753. 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 343 start?
- Area code 343 went into service on May 17, 2010 as an overlay of 613.
- Is a 343 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 343 have?
- 641 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.
- Does a valid format mean a 343 number is in service?
- No. A format check only says the digits fit the North American Numbering Plan and that 343 is an assigned code. It cannot tell whether the number is connected, who answers it or which carrier serves it today, because numbers are reassigned and ported. A live carrier lookup reports the current carrier and line type, but even that is not proof someone answers.
- Can I check a list of 343 numbers for free?
- Yes. Paste them in the list tab above or upload a CSV to the bulk phone number validator: format, E.164, country and the numbering-plan line type are free for every row, with no account. Live carrier and line-type lookups come with Pro + Phone at $49.99/mo (5,000 a month).
Other area codes in Ontario
All Ontario area codes on the area code index.
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.