Phone prefixes in Cobourg, ON

In numbers

In-service prefixes

25

Telephone numbers covered

250,000

Carriers

11

Area codes

4

Provinces and territories

1

First assignment

January 29, 2001

Most recent assignment

December 27, 2024

Cobourg’s share of its area codes

Within area code 289, Cobourg accounts for only 8 of 772 prefixes (1.0%): the code is dominated by Hamilton and spread over 87 rate centres. Within area code 905, Cobourg accounts for only 8 of 773 prefixes (1.0%): the code is dominated by Hamilton and spread over 94 rate centres. Within area code 365, Cobourg accounts for only 6 of 702 prefixes (0.9%): the code is dominated by Markham and spread over 88 rate centres. Within area code 742, Cobourg accounts for only 3 of 146 prefixes (2.1%): the code is dominated by Brampton and spread over 68 rate centres.

Who holds these numbers

Bell Canada holds the largest share at 5 prefixes, 20.0% of the total, ahead of 10 other carriers. Code by code: in 289, Rogers Communications Canada Inc. (Wireless) leads with 2 of 8 prefixes ahead of 6 others; in 905, Bell Canada leads with 4 of 8 prefixes ahead of 2 others; in 365, Iristel Inc. leads with 4 of 6 prefixes ahead of 2 others; in 742, Videotron Ltd. leads with 1 of 3 prefixes ahead of 2 others. No carrier holds prefixes in every one of Cobourg’s 4 area codes, while 6 appear in just one.

Wireless and wireline

9 of Cobourg’s 25 prefixes (36.0%) are held by carriers whose registered name marks a wireless business: Bell Mobility, TELUS Mobility, Rogers Communications Canada Inc. (Wireless) and Fido Solutions Inc. Wireline prefixes still outnumber them, carried by Bell Canada, Iristel Inc, Videotron Ltd and Cogeco Connexion Inc. This is a sort by name, not a licence lookup, and a mobile prefix may have been ported to another network since.

How the allocation was built up

Cobourg’s dated assignments run from 2001 to 2024. The busiest period was 2015–2019, when 6 prefixes went to 3 carriers. 6 prefixes (24%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 4 prefixes have been added, so the rate centre is still growing.

Cobourg’s oldest prefixes, the ones the register leaves undated, belong to Bell Canada, Bell Mobility and TELUS Mobility: these carriers made up the landscape before competition arrived. The first dated assignment went to Rogers Communications Canada Inc. (Wireless) in 2001. The most recent arrivals are Cogeco Connexion Inc. (2024), Rogers Communications Canada Inc. (Cable) (2024) and Videotron Ltd. (2018), a sign that new carriers are still asking for numbers in Cobourg.

Cobourg has only 25 prefixes, or 250,000 numbers: a small rate centre, where the arrival of a single new carrier visibly changes the landscape.

No single carrier dominates Cobourg: the leader, Bell Canada, holds only 20.0% of the prefixes against 10 competitors, a sign of a highly fragmented market where cable companies, mobility brands and VoIP providers weigh as much as the incumbent.

Demand remains steady: 21.1% of the dated prefixes go back to the last ten years, the most active period being 2015–2019. The rate centre is growing at a regular rather than explosive pace.

6 undated in the register.

Dialling a Cobourg number

Cobourg is served by 4 overlaid area codes (289, 905, 365 and 742). A 742 number is no more “out of town” than a 289 one; from abroad, dial +1 and the full ten digits.

The numbering neighbourhood

Cobourg shares area codes 289, 905, 365 and 742 with at least 20 other rate centres, including Hamilton, Brampton, Oshawa, St. Catharines-Thorold, Oakville, Markham, Ajax-Pickering and Cooksville. The largest of them, Hamilton, holds 221 prefixes in 289, 365, 742 and 905; the smallest on the list, Dunnville, has just 28.

What a Cobourg number tells you

A number attached to Cobourg tells you that its prefix was issued to a carrier for this rate centre in Ontario, most often Bell Canada. It does not tell you where the handset is today: a subscriber may have ported the number to any of the 11 carriers present here or to a VoIP service usable anywhere. Nor does it tell you who is calling: caller ID can be spoofed, and an Ontario area code is easy to borrow to look local.

Reading a register entry for Cobourg: code 905-372 is recorded for Bell Canada, so every 905-372-XXXX number (10,000 possible) descends from that assignment. “Cobourg, Ontario” there names a rate centre, not a municipality, and several area codes overlay it.

Every Cobourg prefix

Each row is an in-service central-office code recorded for Cobourg, with its original holder and year of assignment.

Allocated prefixes

All 25 in-service prefixes, grouped by rate centre.

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