Phone prefixes in Grimsby, ON

In numbers

In-service prefixes

16

Telephone numbers covered

160,000

Carriers

12

Area codes

3

Provinces and territories

1

First assignment

December 22, 2005

Most recent assignment

August 9, 2023

Grimsby’s share of its area codes

Within area code 289, Grimsby accounts for only 9 of 772 prefixes (1.2%): the code is dominated by Hamilton and spread over 87 rate centres. Within area code 365, Grimsby accounts for only 5 of 702 prefixes (0.7%): the code is dominated by Markham and spread over 88 rate centres. Within area code 905, Grimsby accounts for only 2 of 773 prefixes (0.3%): the code is dominated by Hamilton and spread over 94 rate centres.

Who holds these numbers

Iristel Inc. holds the largest share at 3 prefixes, 18.8% of the total, ahead of 11 other carriers. Code by code: in 289, Iristel Inc. leads with 2 of 9 prefixes ahead of 7 others; in 365, Fibernetics Corporation leads with 2 of 5 prefixes ahead of 3 others; Bell Canada is the only holder in 905. No carrier holds prefixes in every one of Grimsby’s 3 area codes, while 11 appear in just one.

Wireless and wireline

1 of Grimsby’s 16 prefixes (6.3%) are held by carriers whose registered name marks a wireless business: TELUS Mobility. Wireline prefixes still outnumber them, carried by Iristel Inc, Bell Canada, Fibernetics Corporation and Beanfield Technologies 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

Grimsby’s dated assignments run from 2005 to 2023. The busiest period was 2005–2009, when 5 prefixes went to 5 carriers. 2 prefixes (13%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 5 prefixes have been added, so the rate centre is still growing.

Grimsby’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 TELUS Integrated Communications in 2005. The most recent arrivals are Beanfield Technologies Inc. (2021), Fibernetics Corporation (2020) and TekSavvy Solutions Inc (2020), a sign that new carriers are still asking for numbers in Grimsby.

Grimsby has only 16 prefixes, or 160,000 numbers: a small rate centre, where the arrival of a single new carrier visibly changes the landscape.

No single carrier dominates Grimsby: the leader, Iristel Inc., holds only 18.8% of the prefixes against 11 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: 35.7% of the dated prefixes go back to the last ten years, the most active period being 2005–2009. The rate centre is growing at a regular rather than explosive pace.

2 undated in the register.

Dialling a Grimsby number

Grimsby is served by 3 overlaid area codes (289, 365 and 905). A 905 number is no more “out of town” than a 289 one; from abroad, dial +1 and the full ten digits.

The numbering neighbourhood

Grimsby shares area codes 289, 365 and 905 with at least 20 other rate centres, including Hamilton, Oshawa, Brampton, St. Catharines-Thorold, Oakville, Markham, Cooksville and Ajax-Pickering. The largest of them, Hamilton, holds 213 prefixes in 289, 365 and 905; the smallest on the list, Woodbridge, has just 28.

What a Grimsby number tells you

A number attached to Grimsby 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 12 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 Grimsby: code 289-205 is recorded for Iristel Inc., so every 289-205-XXXX number (10,000 possible) descends from that assignment. “Grimsby, Ontario” there names a rate centre, not a municipality, and several area codes overlay it.

Every Grimsby prefix

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

Allocated prefixes

All 16 in-service prefixes, grouped by rate centre.

Elsewhere in Ontario