Area Code 343

About Area Code 343

Area code 343 is a geographic telephone area code assigned to Ottawa, Ontario. It operates in the Eastern time zone and was first introduced in 2010. Overlay for 613. Eastern Ontario. Overlay 753 added 2022.

Within Ontario, area code 343 operates alongside 15 other area codes. The province's 2023 population estimate is 15,996,389. Ontario's capital is Toronto and its largest city is Toronto.

When you receive a call from a 343 number on your Caller ID, the call originated from a phone number assigned to the 343 area code — but be aware that Local Number Portability (in effect since 2003) means the caller could be physically located anywhere in the US or Canada. Area code 343 only confirms where the number was originally assigned.

Where is the 343 area code located?

Area code 343 is assigned to Ottawa, Ontario, in the Eastern time zone. The state of Ontario uses 16 active area codes, and 343 is one of them. Calls placed from the 343 area code originate from numbers assigned by NANPA — the North American Numbering Plan Administrator — and the 343 prefix appears on Caller ID for both landline and wireless calls placed from this region.

The Eastern time zone observes Daylight Saving Time, shifting from UTC-5 to UTC-4 in summer. The local time shown above is always current, so you can quickly check whether it's a reasonable hour to call back.

What cities and counties use the 343 area code?

The 343 area code serves 11 notable cities, listed below in order of population. The largest city in the 343 territory is Ottawa (1,017,449 residents in Ottawa County).

• Ottawa, ON — 1,017,449 residents (13.5% of 343 numbers)
• Toronto, ON — 2,794,356 residents (37.1% of 343 numbers)
• Mississauga, ON — 717,961 residents (9.5% of 343 numbers)
• Brampton, ON — 656,480 residents (8.7% of 343 numbers)
• Hamilton, ON — 569,353 residents (7.6% of 343 numbers)
• London, ON — 422,324 residents (5.6% of 343 numbers)
• Markham, ON — 338,503 residents (4.5% of 343 numbers)
• Vaughan, ON — 323,103 residents (4.3% of 343 numbers)
• Kitchener, ON — 257,030 residents (3.4% of 343 numbers)
• Windsor, ON — 229,660 residents (3.1% of 343 numbers)

Phone number format in area code 343

All phone numbers within area code 343 follow the standard North American 10-digit format:(343) NXX-XXXX. The NXX is the central office prefix (also called an "exchange") and XXXX is the subscriber line number. For long-distance calls within the NANP, dial 1 + 343 + NXX + XXXX. From outside North America, dial your country's international access code, then 1 (the NANP country code), then the 10-digit number.

If you need to verify whether a specific 343 number is wireless, landline, or VoIP, you can use our reverse phone lookup tool. Be aware that number portability means the area code no longer guarantees the caller's physical location — only where the number was first assigned.

History of area code 343

Overlay for 613. Eastern Ontario. Overlay 753 added 2022.

The original 86 area codes were assigned by AT&T and Bell Labs in 1947 as part of the North American Numbering Plan. At the time, rotary-dial phones meant codes with lower digits (like 212 for NYC, 213 for LA, 312 for Chicago) were given to the largest cities because they took less time to dial. Today's area code assignments still reflect those early choices, even though touch-tone and cell phones made the original reason obsolete.

Is the 343 area code safe to answer?

Area code 343 itself is a normal geographic code with no elevated spam risk. That said, scammers can spoof any area code — including 343 — so if you don't recognize the full number, let it go to voicemail and verify the caller's identity before calling back.