Area Code Atlas

NANP - REMINDER OF FEBRUARY 1, 1991 DATE FOR ELIMINATION OF THE USE OF THE 706 AND 905 NPA CODES FOR CALLS TO MEXICO

Area code 905 retired for calls to Mexico

Area code 905 was used for special call routing to Mexico City during the 1960s to 1980s. This arrangement was terminated on December 28, 1990, as Mexico established its own country code 52.

Area code 905 introduced for Golden Horseshoe region

Area code 905 was created in October 1993 as a split from area code 416 to serve the Golden Horseshoe region surrounding Lake Ontario in Southern Ontario, Canada. Automatic number identification started operation on October 11, 1992, and the new area code entered service on October 11, 1993.

Establishment of area code 905 in a split from 416

In October 1993, area code 905 was established in a split from area code 416, serving the Golden Horseshoe region surrounding Toronto. The split was implemented to address rapid growth and number exhaustion in the Toronto metropolitan area.

NPA 905 split from 416

Area code 905 was created on October 2, 1993, by splitting the 416 numbering plan area. The 416 area was reduced to Metro Toronto, while 905 served the surrounding Golden Horseshoe suburbs.

Permissive dialing period begins for 416 and 905

Permissive dialing for both area codes 416 and 905 began on October 2, 1993, allowing calls to be completed using either code during the transition period following the split. This period was intended to ease the transition after the split.

Establishment of area code 905 in a split from 416

On October 11, 1993, area code 905 was established in southern Ontario as a split from area code 416. The new code served the Golden Horseshoe region surrounding Toronto, while 416 was retained for the City of Toronto.

Area code 905 introduced as a split from 416

Area code 905 was created in October 1993 as a split from area code 416 to serve the Golden Horseshoe region surrounding Lake Ontario in Southern Ontario, Canada. This split was necessitated by rapid growth and telecommunications demand in the region. Permissive dialing of 416 continued until January 1, 1994.

Mandatory ten-digit dialing introduced with 289 overlay planning

Permissive dialing of area code 416 continued across the Golden Horseshoe until January 1, 1994, after which ten-digit dialing became mandatory in preparation for future overlays.

Mandatory dialing for 416 and 905

Mandatory dialing for area codes 416 and 905 began on March 26, 1994, ending the permissive period and requiring callers to use the correct area code for calls within the region.

Permissive dialing period for 416/905 split ends

Permissive dialing, allowing calls to be completed using either 416 or 905, ended on March 26, 1994, after the 1993 split. After this date, dialing the correct area code became mandatory.

Overlay relief planned for area code 905 with introduction of 289

The Canadian Radio-television and Telecommunications Commission (CRTC) approved area code 289 as an overlay to area code 905 in August 2000 to address the rapid exhaustion of numbers in the 905 region. This overlay was chosen over a geographic split to minimize disruption and to implement ten-digit dialing.

NPA 289 overlay on 905 announced

NPA 289 To Overlay NPA 905 (Southern Ontario, Canada)

Permissive ten-digit dialing begins in 905 region

Permissive dialing allowing both seven-digit and ten-digit local calls began in the 905 region in April 2001 in preparation for the activation of the 289 overlay.

NPA 289 overlaid on 905

Area code 289 was introduced as an overlay on the 905 region on June 7, 2001, due to the rapid exhaustion of available numbers. The overlay required the implementation of ten-digit dialing for all local calls within the region.

Area code 289 overlaid on 905

Area code 289 was introduced as an overlay to area code 905 on June 9, 2001, to provide relief for number exhaustion in the Golden Horseshoe region. This overlay required ten-digit dialing for all local calls.

CRTC announces overlay of area code 365

On April 13, 2010, the CRTC announced that area code 365 would be overlaid on the existing 905 and 289 area codes to provide further relief for the Golden Horseshoe region. The overlay was planned in response to the continued growth and projected exhaustion of numbering resources.

NPA 365 overlay on 289/905 announced

NPA 365 to Overlay NPA 289/905 (Southern Ontario, Canada)

NPA 365 overlay on 289/905 announced

NPA 365 to Overlay NPA 289/905 (Southern Ontario, Canada)

NPA 365 overlay on 289/905 announced

NPA 365 to Overlay NPA 289/905 (Southern Ontario, Canada)

Area code 365 overlaid on 905/289 complex

Area code 365 was added as a third overlay to the 905/289 numbering plan area on March 25, 2013, to address continued growth and number exhaustion in the Golden Horseshoe region.

Area code 365 activated as overlay

Area code 365 became operational on March 25, 2013, as an overlay to the existing 905 and 289 area codes in the Golden Horseshoe region, providing additional numbering capacity.

CRTC decision to implement area code 742 overlay

On October 28, 2020, the CRTC determined that relief for area codes 289, 365, and 905 would be provided by implementing a distributed overlay of new area code 742, with an effective date set for October 16, 2021.

NPA 742 overlay on NPA 289/365/905 (Southern Ontario)

NPA 742 overlay on 289/365/905 announced

NPA 742 to Overlay NPA 289/365/905 (Southern Ontario, Canada) – supersedes PL-550

Area code 742 added as fourth overlay to 905 complex

Area code 742 was introduced on October 16, 2021, as the fourth overlay area code for the Golden Horseshoe region, overlaying the existing 905, 289, and 365 area codes to provide additional numbering resources.

Area code 537 reserved for future relief in Golden Horseshoe

In November 2022, area code 537 was reserved by the CRTC as a fifth area code for future relief in the Golden Horseshoe region, to be activated when the existing overlay complex approaches exhaustion.

Area code 537 reserved for future relief in Golden Horseshoe

Area code 537 was reserved on November 8, 2022, as a fifth area code for future relief of the numbering plan area covering the Golden Horseshoe region in Ontario, Canada.