Phone prefixes in Oshawa, ON

In numbers

In-service prefixes

110

Telephone numbers covered

1,100,000

Carriers

20

Area codes

4

Provinces and territories

1

First assignment

December 22, 1999

Most recent assignment

March 7, 2025

Oshawa’s share of its area codes

Within area code 905, Oshawa accounts for only 49 of 773 prefixes (6.3%): the code is dominated by Hamilton and spread over 94 rate centres. Within area code 289, Oshawa accounts for only 36 of 772 prefixes (4.7%): the code is dominated by Hamilton and spread over 87 rate centres. Within area code 365, Oshawa accounts for only 23 of 706 prefixes (3.3%): the code is dominated by Markham and spread over 88 rate centres. Within area code 742, Oshawa accounts for only 2 of 148 prefixes (1.4%): the code is dominated by Brampton and spread over 68 rate centres.

Who holds these numbers

Bell Canada holds the largest share at 22 prefixes, 20.0% of the total, ahead of 19 other carriers. Code by code: in 905, Bell Canada leads with 20 of 49 prefixes ahead of 8 others; in 289, Bell Mobility leads with 5 of 36 prefixes ahead of 12 others; in 365, Iristel Inc. leads with 9 of 23 prefixes ahead of 11 others; in 742, Fibernetics Corporation leads with 1 of 2 prefixes ahead of 1 others. No carrier holds prefixes in every one of Oshawa’s 4 area codes, while 9 appear in just one.

Wireless and wireline

40 of Oshawa’s 110 prefixes (36.4%) are held by carriers whose registered name marks a wireless business: Bell Mobility, Rogers Communications Canada Inc. (Wireless), TELUS Mobility and Fido Solutions Inc. Wireline prefixes still outnumber them, carried by Bell Canada, Iristel Inc, Rogers Communications Canada Inc. (Cable) and Videotron Ltd. 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

Oshawa’s dated assignments run from 1999 to 2025. The busiest period was 2005–2009, when 18 prefixes went to 10 carriers. 29 prefixes (26%) carry no date in the register: these are the historic pre-1999 assignments, the wireline bedrock of the rate centre. Since 2020 another 13 prefixes have been added, so the rate centre is still growing.

Oshawa’s oldest prefixes, the ones the register leaves undated, belong to Bell Canada, Rogers Communications Canada Inc. (Wireless) and TELUS Mobility: 6 carriers made up the landscape before competition arrived. The first dated assignment went to Rogers Communications Canada Inc. (Wireless) in 1999. The most recent arrivals are Beanfield Technologies Inc. (2021), TekSavvy Solutions Inc (2021) and IXICA Communications Inc. (2020), a sign that new carriers are still asking for numbers in Oshawa.

Its 110 prefixes stand for 1,100,000 possible numbers: Oshawa is a large rate centre, the kind that hosts several switching offices and a sizeable business clientele.

No single carrier dominates Oshawa: the leader, Bell Canada, holds only 20.0% of the prefixes against 19 competitors, a sign of a highly fragmented market where cable companies, mobility brands and VoIP providers weigh as much as the incumbent.

Allocation is mature: only 16.0% of the dated prefixes are less than ten years old, most having been handed out in 2005–2009, and 29 prefixes go back to the undated monopoly era. New Oshawa numbers mostly come out of blocks that were assigned long ago.

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

29 undated in the register.

Dialling a Oshawa number

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

The numbering neighbourhood

Oshawa shares area codes 905, 289, 365 and 742 with at least 20 other rate centres, including Hamilton, Brampton, St. Catharines-Thorold, Oakville, Markham, Ajax-Pickering, Cooksville and Thornhill. The largest of them, Hamilton, holds 222 prefixes in 289, 365, 742 and 905; the smallest on the list, Maple, has just 28.

What a Oshawa number tells you

A number attached to Oshawa 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 20 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 Oshawa: code 905-404 is recorded for Bell Canada, so every 905-404-XXXX number (10,000 possible) descends from that assignment. “Oshawa, Ontario” there names a rate centre, not a municipality, and several area codes overlay it.

Every Oshawa prefix

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

What people check and report about Oshawa numbers

Searches typed into this site's lookup form since July 28, 2026, plus the verdicts and moderated reports visitors left. A search usually follows a missed call.

Checks

32

Different numbers

32

Different people

32

Had a call from a Oshawa number?

No clear pattern in reports on these numbers yet. If a call worried you:

1. Call back on a number you trust

   If a caller says they are your bank, the Canada Revenue Agency, a courier or your phone company, hang up and call the organization on the number from its website or your statement, never the number that called you. Caller ID can be faked.

2. Report the fraud

   Report the call or text to the Canadian Anti-Fraud Centre online or at 1-888-495-8501. If you lost money or gave out personal details, tell your bank first, then your local police.

   Report to the Canadian Anti-Fraud Centre ↗

3. Register on the National Do Not Call List

   Registering a landline or mobile on the National DNCL is free. Registered charities, political parties, newspapers and companies you already do business with may still call.

   National Do Not Call List ↗Who can still call you ↗

4. Forward suspicious texts to 7726

   Forward a scam or spam text to 7726 (SPAM on the keypad). It's free, and your carrier uses it to block the sender. Don't tap links or reply.

   Get Cyber Safe: forwarding to 7726 ↗

Allocated prefixes

All 110 in-service prefixes, grouped by rate centre.

Elsewhere in Ontario