A taxable person files the corporate tax return no later than 9 months from the end of the tax period, and the same deadline applies to paying: payment is due within 9 months. For a financial year that ended on 31 December 2025, the FTA set the date at 30 September 2026.
Work it out from your own year end
Because the clock starts at your year end, two businesses in the same building can have different deadlines. Three common cases:
| Financial year ends | Return and payment due |
|---|---|
| 31 December 2025 | 30 September 2026 |
| 31 March 2026 | 31 December 2026 |
| 30 June 2026 | 31 March 2027 |
The nine months are calendar months from the end of the period, not nine months from when your accountant finishes. The FTA's September 2026 statement put it plainly for calendar-year businesses: returns and payment for the year ended 31 December 2025 were due by the end of September 2026.
The other date in your year
If you are VAT registered, the more frequent deadline is the VAT one: the return and the payment are due 28 days after the end of the tax period, and the standard period is three calendar months. So a typical registered business has four VAT dates and one corporate tax date in a year, which is why VAT dominates the monthly rhythm of bookkeeping even though corporate tax gets the attention.
Chart data
| Return | Due |
|---|---|
| VAT return | 28 days after the period |
| Corporate tax return and payment | 9 months after year end |
Paying is a separate act from filing
Filing the return does not pay the tax, and submitting early does not move the payment date earlier. Both sit on the same deadline, which means a business that files in July for a December year end still has until 30 September to move the money. Treat the gap as working capital planning rather than a grace period: the amount is known once the return is done.
Relief does not change the date
Businesses eligible for Small Business Relief file a simplified return, and the FTA has stressed that this is elected in the return. The deadline is the same one. A zero tax bill with a late return is still a late return.
What to have ready before the deadline month
The FTA lists the essential records as transactions, assets, liabilities and ownership interests, and they must be kept for 7 years after the end of the period they relate to. In practice the businesses that file calmly are the ones that closed each month during the year. The ones that file in the last fortnight are usually reconstructing bank lines from statements, which is also when accountants charge their worst rates.
Amounts for late filing
We do not publish them. Penalty amounts are set by Cabinet decision, and we could not verify the current official text on 12 September 2026. What is officially stated is the consequence in principle: administrative penalties apply where records are not kept. For the amounts, check the FTA legislation page or ask a registered tax agent.
The calculator on the corporate tax page shows your next deadline for any financial year end.