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Area code 403

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History

Area code 403 was one of nine Canadian area codes of the original North American area codes assigned by the American Telephone and Telegraph Company (AT&T) in 1947. Its numbering plan area (NPA) originally comprised the entire province of Alberta. During the course of the expansion of telephone service in the Canadian territories, these were serviced primarily with the same area code until the territories received area code 867 on October 21, 1997.

Within only a year, area code 403 was threatened by exhaustion because of the rapid growth of telecommunication services demand for pagers, cellphones, and computer modems, as well as growing competition among providers. On January 25, 1999, the northern two thirds of Alberta, including Edmonton, was split from 403 and assigned the new area code 780. Generally, everything from Red Deer, Lacombe, and Ponoka southward stayed in 403. Permissive dialing of 403 continued across the province until May 18, 1999.

Within a decade, area code 403 was close to exhaustion once again. The projected exhaust date was March 2009. The solution for mitigation was to implement area code 587 as a province-wide overlay for both numbering plan areas of the province. Optional ten-digit dialing began on June 23, 2008 and became mandatory on September 12, 2008. On September 20, 2008, Telus Mobility began to assign 587 telephone numbers to new customers in Calgary and Edmonton.

On April 9, 2016, all three numbering plan areas of the province were overlaid with an additional area code, 825.

On January 21, 2022, the province was once again overlaid with another area code, 368.

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