Ontario, Canada
Eastern Time
3:16 AM
Area Code
343
State / Province
Ontario
Country
Canada
Time Zone
Eastern Time
Area code 343 covers 116 cities and communities across Ontario, based on telephone company rate center data.
Use the E.164 format for clickable phone links (RFC 3966):
<a href="tel:+13435550100">+13435550100</a><a href="tel:+13435550199">+13435550199</a>343 now shares its territory with 753. Because of this overlay, local calls in this region must be dialed with all ten digits.
Area code 343 is a North American Numbering Plan (NANP) telephone area code assigned to Ontario, Canada. It is one of 19 area codes serving Ontario. As population and demand for phone numbers grew, the region was divided into multiple numbering plan areas to avoid exhausting the available 7-digit number pool.
Yes. 343 is an active North American Numbering Plan (NANP) area code, currently assigned to Ontario, Canada. It is safe to answer or dial calls using this area code.
Area code 343 covers 116 cities and communities in Ontario, including Adolphustown, Alexandria, Alfred, Almonte, Arden, and 111 more localities. This is based on telephone company rate center data — the geographic areas carriers use to determine local calling boundaries and to assign numbers when a business or individual requests a phone number in a specific city.
All numbers in the 343 area code observe Eastern Time (IANA timezone: America/New_York). Eastern Time is UTC−5 in winter (EST) and UTC−4 in summer (EDT). When placing a call to a 343 number from a different time zone, check the current local time above to avoid calling outside of business hours.
From within Ontario, dial the 7-digit local number directly if calling within the same rate center, or dial 1 + 343 + 7-digit number for long-distance calls within North America. From outside the US or Canada, dial your country's international exit code followed by 1 343 XXX XXXX. The country code for both the United States and Canada in NANP is +1.
Format 343 numbers using E.164 notation as required by RFC 3966: prefix with +1 and omit dashes and parentheses (e.g., +13435550100). This format ensures tel: links work correctly on all mobile browsers and VoIP apps. See the tel: URI formatting guide for complete examples.