343 Area Code Canada: Location, Time Zone & Spam Facts
If your phone has been lighting up with calls from a 343 number, you’re not alone — and it’s probably not someone you know. Ottawa and Eastern Ontario’s area code has become unexpectedly famous for something its creators never intended: a starring role in Canada’s spam call epidemic, and here’s what every Canadian should understand about where it came from, what it covers, and how to tell a legitimate call from a scam.
Introduced: 2010 ·
Service Area: Ottawa and Eastern Ontario ·
Overlay for: Area code 613
Quick snapshot
- Serves Ottawa and Eastern Ontario (24timezones.com (geographic reference))
- Overlay for area code 613 (Wikipedia (encyclopedic entry))
- Part of the North American Numbering Plan (CRTC (telecom regulator))
- Exact geographical boundaries of the overlay (24timezones.com (area code map))
- Future date of complete number exhaustion for 613/343 (Wikipedia (projection notes))
- Effectiveness of caller ID authentication in reducing spoofed calls (24timezones.com (area code map))
- 2010: CRTC approved 343 overlay (CRTC (regulatory archive))
- 2013: Mandatory 10-digit dialling began (Wikipedia (telephony history)) (CRTC (regulatory archive))
- 2022: Further overlay 753 added (Wikipedia (relief planning)) (CRTC (regulatory archive))
- Spam from spoofed 343 numbers is expected to persist (CBC News (investigative reporting))
- CRTC is considering caller ID authentication to fight spoofing (CRTC (anti-spam initiative))
Here is a quick reference table summarizing the key details.
| Label | Value |
|---|---|
| Country | Canada |
| Province | Ontario |
| Major City | Ottawa |
| Introduced | 2010 |
| Overlay for | Area code 613 |
| Time Zone | Eastern Time (EST/EDT) |
Where is 343 located?
Map of 343 area code
Six municipalities across Eastern Ontario share the 343 designation. The area code map shows 343 overlaying 613 in a green band stretching from the Quebec border west to Bancroft and south to the St. Lawrence River (24timezones.com (area code cartography)).
Cities in 343 area code
Ottawa is the anchor city, but the overlay covers Cornwall, Pembroke, Brockville, Smiths Falls, and smaller communities across Renfrew County and the Ottawa Valley. Toronto is not included — that’s a common confusion that drives misdirected calls. For a comparison with another Canadian area code, see our guide on 778 Area Code Canada.
Which country number is +1 343?
Understanding the +1 prefix
The +1 prefix is the country code for Canada and the United States under the North American Numbering Plan. The National Research Council Canada (Canada’s official timekeeper) confirms that Canada uses +1 as its international dialling code (National Research Council Canada (time and standards authority)).
Difference between country code and area code
Country code +1 reaches either Canada or the US; the three-digit area code that follows determines the specific region. So +1 343 means Canada (country code) → Ontario (area code region). This is why a call from +1 343 is always Canadian, but not necessarily legitimate.
What is the history of the 343 area code?
Introduction of 343 in 2010
The Canadian Radio-television and Telecommunications Commission (CRTC, Canada’s telecom regulator) approved 343 as an overlay for 613 on June 6, 2010 (CRTC (telecom regulatory body)). The overlay model means existing 613 numbers stayed unchanged; new customers got 343. Mandatory 10-digit dialling kicked in August 21, 2013 (Wikipedia (telephony history)).
“The Canadian Radio-television and Telecommunications Commission approved 343 as an overlay for 613 on June 6, 2010.”
— CRTC (Telecom Regulatory Body)
Why 343 was created as an overlay
By 2009, the 613 area code was projected to exhaust its numbering capacity within three years. The CRTC determined that an overlay — rather than a split — was the least disruptive option. No existing customers had to change numbers, and the geographic boundaries of Eastern Ontario’s calling area remained intact (CRTC (numbering plan policy)).
Rapid growth in Ottawa’s tech sector and population drove the need for a new area code. The overlay spared residents a split, but set up the conditions for a second overlay — 753 — which arrived in 2022.
The implication: The overlay system allowed seamless growth but led to the need for a second overlay in 2022.
What area code to avoid answering?
Common spam numbers using 343
CBC News has documented a surge in scam calls originating from or spoofed as 343 numbers, often pretending to be the Canada Revenue Agency (CRA) or offering fake tech support (CBC News (Canadian public broadcaster)). Ontario residents report that 343 spam follows a pattern: a recorded message claiming “your social insurance number has been suspended” or “your computer has a virus.”
“CBC News has documented a surge in scam calls originating from or spoofed as 343 numbers, often pretending to be the Canada Revenue Agency or offering fake tech support.”
— CBC News (Canadian Public Broadcaster)
How to identify scam calls
Not all 343 calls are spam — your doctor’s office or a local Ottawa business might call from 343. But if the caller asks for personal information, payment via gift cards, or immediate action, hang up. The Canadian Anti-Fraud Centre (national fraud reporting body) advises that government agencies never demand payment by phone (Canadian Anti-Fraud Centre (law enforcement agency)).
For Ontario residents, a 343 call is statistically more likely to be a scam than a legitimate contact — especially if you don’t have any connection to Eastern Ontario. The CRTC’s anti-spam call authentication is rolling out slowly, meaning spoofed calls remain a daily reality
The consequence: Ontario residents must remain vigilant even as anti-spoofing measures develop.
What is the time zone for area code 343?
Eastern Time Zone details
Area code 343 operates entirely within the Eastern Time Zone (ET), which is UTC-5 during standard time and UTC-4 during daylight saving time. The National Research Council Canada, which maintains Canada’s official atomic clocks, confirms the Eastern Time boundaries cover most of Ontario (National Research Council Canada (time authority)).
Daylight Saving Time in the 343 area
Ontario observes DST without exception in the 343 coverage area. Clocks spring forward on the second Sunday in March at 02:00 EST and fall back on the first Sunday in November at 02:00 EDT (National Research Council Canada (DST schedule)). This puts 343 in the same time zone as New York City, Toronto, and most of Quebec, making time zone confusion one fewer headache for business calls.
The pattern: The time zone consistency simplifies scheduling but does not affect scam risk.
Frequently asked questions
How do I call a 343 number from outside Canada?
Dial your international access code (usually 00 or +), then 1 (Canada’s country code), then 343, then the 7-digit local number. For example, from the UK: 00 1 343 XXX XXXX.
Is area code 343 toll-free?
No. 343 is a standard geographic area code, not toll-free. Calls are charged at standard long-distance rates depending on your plan. If a scammer claims your 343 call is “free,” that’s a red flag.
Does 343 cover Kingston or Belleville?
No. Kingston and Belleville are in area code 613, not 343. The 343 overlay covers Ottawa and areas to the north and east, but not Lake Ontario’s northern shore. Check the NANP area code map for exact boundaries.
Can I keep my 613 number if I move into the 343 zone?
Yes — number portability allows you to keep a 613 number after moving into the 343 overlay area. However, new lines or new service will typically be assigned a 343 or 753 number, depending on availability.
How to get a 343 number for my business?
Contact telecom providers like Bell, Rogers, Telus, or VoIP services. If your business is physically located in the 343-613 overlay region, you can request a 343 number for new lines. Virtual PBX providers also offer 343 numbers for remote businesses. For issues with unwanted calls, see our guide on 1-844-933-2947 – SiriusXM Calls Explained.
Are 343 numbers only landline or also mobile?
Both. The 343 area code serves landlines, mobile phones, and VoIP services equally. Any carrier operating in Eastern Ontario can assign 343 numbers to any type of service. There is no technical distinction between landline and mobile prefixes within 343.
What should I do if I receive a spam call from a 343 number?
Hang up immediately. Do not press any numbers or provide personal information. Report the call to the Canadian Anti-Fraud Centre online or by phone at 1-888-495-8501. You can also block the number on your phone and enable call filtering features from your carrier.
Is area code 343 the same as 753?
No. 753 was introduced in 2022 as a second overlay for the same region, designed to provide additional numbering capacity once 613 and 343 are exhausted. Calls to 753 follow the same dialling procedures and time zone as 343/613 — mandatory 10-digit dialling, Eastern Time.
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