The eastern part of Quebec received area code 418, while area code 514 was assigned for the western part. Nominally, northwestern Quebec, one of the few areas of North America without telephone service, was reassigned from area code 514 to area code 418 in 1957. From the 1950s to the 1970s, area code 418 was also the area code for the eastern Northwest Territories. However, in the 1970s, as direct distance dialling was introduced to the far northern and western portions of 418, those areas were reassigned to area code 819.
Despite Quebec City's rapid growth, by the turn of the millennium, area code 418 was the last of Quebec and Ontario's original four area codes not to have been split. By 2006, however, area code 418 was on the brink of exhaustion because of Canada's system of number allocation. Every competitive local exchange carrier is allocated blocks of 10,000 numbers, which correspond to a single three-digit prefix, for every rate centre in which it plans to offer service, even for small hamlets. Once a number is assigned to a carrier and rate centre, it cannot be moved elsewhere even if a rate centre has more than enough numbers to serve it. That resulted in thousands of wasted numbers, a problem that was worsened by the proliferation of cellphones and pagers, especially in the larger cities. Additionally, a number of "megacities" created in 2002 are split between multiple rate centres, which have never been amalgamated. For example, Saguenay is split between four rate centres.
In 2007, the CRTC assigned area code 581 as an overlay for 418. The implementation of area code 581 began on June 21, 2008 with the start of a permissive dialing period during which local calls could be made with both seven and ten digits. Ten-digit dialing became mandatory in eastern Quebec on September 6, 2008.[1][2]
By 2016, area codes 418 and 581 were again on the brink of exhaustion because of the further proliferation of cell phones and pagers. In 2017, the CRTC assigned area code 367 as a second overlay for eastern Quebec. It entered service in 2018.[3] That had the effect of assigning 23.4 million numbers to only 1.8 million people. However, overlays have become the preferred method of relief in Canada, as they are an easy workaround for the number allocation problem. No area codes have been split in the country since 1999.
