Phone prefixes in St. Thomas, ON

In numbers

In-service prefixes

15

Telephone numbers covered

150,000

Carriers

7

Area codes

3

Provinces and territories

1

First assignment

May 30, 2005

Most recent assignment

October 9, 2024

St. Thomas’s share of its area codes

Within area code 548, St. Thomas accounts for only 6 of 499 prefixes (1.2%): the code is dominated by London and spread over 170 rate centres. Within area code 226, St. Thomas accounts for only 5 of 778 prefixes (0.6%): the code is dominated by London and spread over 166 rate centres. Within area code 519, St. Thomas accounts for only 4 of 779 prefixes (0.5%): the code is dominated by London and spread over 210 rate centres.

Who holds these numbers

Iristel Inc. holds the largest share at 5 prefixes, 33.3% of the total, ahead of 6 other carriers. Code by code: in 548, Iristel Inc. leads with 2 of 6 prefixes ahead of 3 others; in 226, Iristel Inc. leads with 3 of 5 prefixes ahead of 2 others; in 519, Bell Canada leads with 3 of 4 prefixes ahead of 1 others. No carrier holds prefixes in every one of St. Thomas’s 3 area codes, while 5 appear in just one.

Wireless and wireline

1 of St. Thomas’s 15 prefixes (6.7%) are held by carriers whose registered name marks a wireless business: Fido Solutions Inc. Wireline prefixes still outnumber them, carried by Iristel Inc, Bell Canada, Fibernetics Corporation and Rogers Communications Canada Inc. (Cable). 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

St. Thomas’s dated assignments run from 2005 to 2024. The busiest period was 2020–2024, when 6 prefixes went to 3 carriers. 3 prefixes (20%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 6 prefixes have been added, so the rate centre is still growing.

St. Thomas’s oldest prefixes, the ones the register leaves undated, belong to Bell Canada: this carrier made up the landscape before competition arrived. The first dated assignment went to Rogers Communications Canada Inc. (Cable) in 2005. The most recent arrivals are Videotron Ltd. (2023), Fibernetics Corporation (2021) and TELUS Integrated Communications (2019), a sign that new carriers are still asking for numbers in St. Thomas.

St. Thomas has only 15 prefixes, or 150,000 numbers: a small rate centre, where the arrival of a single new carrier visibly changes the landscape.

No single carrier dominates St. Thomas: the leader, Iristel Inc., holds only 33.3% of the prefixes against 6 competitors, a sign of a highly fragmented market where cable companies, mobility brands and VoIP providers weigh as much as the incumbent.

Growth is recent: 50.0% of the dated prefixes were assigned in the last ten years, peaking in 2020–2024. St. Thomas is among the rate centres where demand for numbers is still rising quickly.

The register also shows 1 prefix assigned but not yet in service in St. Thomas (Cogeco Connexion Inc): numbers that will start showing up on call displays in the coming months.

3 undated in the register.

Dialling a St. Thomas number

St. Thomas is served by 3 overlaid area codes (548, 226 and 519). A 519 number is no more “out of town” than a 548 one; from abroad, dial +1 and the full ten digits.

The numbering neighbourhood

St. Thomas shares area codes 548, 226 and 519 with at least 20 other rate centres, including London, Kitchener-Waterloo, Windsor, Guelph, Brantford, Sarnia, Chatham and Hespeler. The largest of them, London, holds 214 prefixes in 226, 519 and 548; the smallest on the list, Essex, has just 16.

What a St. Thomas number tells you

A number attached to St. Thomas tells you that its prefix was issued to a carrier for this rate centre in Ontario, most often Iristel Inc.. It does not tell you where the handset is today: a subscriber may have ported the number to any of the 7 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 St. Thomas: code 548-586 is recorded for Iristel Inc., so every 548-586-XXXX number (10,000 possible) descends from that assignment. “St. Thomas, Ontario” there names a rate centre, not a municipality, and several area codes overlay it.

Every St. Thomas prefix

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

Allocated prefixes

All 15 in-service prefixes, grouped by rate centre.

Elsewhere in Ontario