Area Code Atlas

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.