CRA Deadlines Durham Region Small Businesses Should Watch in October and November 2026
The final quarter is busy for Durham Region businesses. Holiday orders, fall projects, staffing changes, and year-end planning can make a CRA deadline easy to overlook. A missed filing or payment may lead to interest, penalties, and extra administrative work.
This practical calendar highlights common federal deadlines that may affect small businesses in Oshawa, Whitby, Ajax, Pickering, and Clarington during October and November 2026. Your actual obligations depend on your remitter type, reporting period, fiscal year-end, and CRA account details, so confirm each date in CRA My Business Account or with your tax professional.
October 15: payroll remittances for regular and quarterly remitters
Regular payroll remitters generally must send deductions from September payroll by October 15, 2026. This includes income tax, Canada Pension Plan contributions, and Employment Insurance premiums withheld from employees, together with the employer portions.
Eligible quarterly remitters also have an October 15 deadline for deductions made from July 1 through September 30. New small employers and established small employers must meet CRA conditions to qualify for quarterly remitting. Do not assume your business qualifies because payroll is modest; check the remitter type assigned to the payroll account.
Accelerated remitters follow more frequent schedules. If the CRA has assigned your business an accelerated frequency, use those dates rather than the regular monthly deadline.
November 2: quarterly HST returns ending September 30
For many quarterly GST/HST registrants with a reporting period ending September 30, both the return and any balance are normally due one month later. October 31, 2026 falls on a Saturday, so an eligible due date moves to the next business day, Monday, November 2.
Before filing, reconcile sales, HST collected, input tax credits, and payments recorded in the books. Review unusual transactions, personal or mixed-use expenses, vehicle costs, and large equipment purchases. Detailed invoices matter: a credit-card statement by itself may not contain the information needed to support an input tax credit.
Annual filers and businesses with different quarter-ends will have different deadlines. Confirm the reporting period shown on the GST/HST account instead of relying only on a calendar reminder.
November 16: October payroll for regular remitters
October payroll deductions for regular remitters would ordinarily be due November 15. Because November 15, 2026 is a Sunday, the CRA's next-business-day rule generally makes Monday, November 16 the on-time date.
Leave enough processing time for the payment method you use. A payment initiated late in the day may not be credited to the CRA immediately. If you had no employees or only seasonal workers during the period, you may still need to report a nil remittance by the deadline.
Corporate deadlines depend on your fiscal year-end
A corporation must generally file its T2 return within six months after its tax year ends. For example, a corporation with an April 30, 2026 year-end would generally file by October 31; because that date is a Saturday, the next-business-day rule may apply. A May 31 year-end generally leads to a November 30 filing deadline.
The corporate tax balance is usually due two months after year-end, although certain qualifying Canadian-controlled private corporations may have three months. The payment deadline can therefore arrive well before the T2 filing deadline. Corporations may also have monthly or quarterly instalments. Maintain a separate calendar for the return, balance, and instalments so one deadline is not mistaken for another.
Prepare now for December and year-end reporting
October and November are also the right time to review December obligations. Individual income tax instalments may be due December 15 for taxpayers who received an instalment reminder. Employers should confirm employee names, addresses, Social Insurance Numbers, taxable benefits, and year-to-date payroll totals before T4 preparation begins.
Review outstanding customer invoices, contractor payments, capital purchases, shareholder transactions, and unreconciled bank items before the holiday rush. Clean records make HST, payroll, and corporate filings faster and reduce the chance of correcting slips or returns later.
Use a deadline system, not memory
Create one compliance calendar that lists the account, reporting period, filing deadline, payment deadline, responsible person, and confirmation number. Set reminders several business days before each due date and save proof of filing and payment with the period's records.
At Azim Tax & Accounting, we help Durham Region small businesses keep their bookkeeping current, confirm CRA deadlines, and prepare payroll, HST, and income tax filings with supportable records.
Need help organizing your fall CRA deadlines? Read more small business tax guidance or call (647) 570-0313 for a free consultation.