Running a business in Ireland means juggling deadlines across Revenue, the CRO, and employer obligations. Miss one and you’re looking at penalties, interest, or worse. The problem is that the dates shift depending on your business type, your accounting period, your VAT filing frequency, and whether you file through ROS. There’s no single “tax deadline” to remember. There are dozens.
This guide maps out every major deadline for Irish businesses, from corporation tax to VAT to CRO annual returns, so you can build a compliance calendar that works for your specific setup.
What Are the Key Irish Business Deadlines You Must Track Each Year?
Irish business deadlines fall into three buckets:
- Revenue deadlines: Corporation tax, income tax, VAT, PAYE/PRSI/USC, preliminary tax, Return of Trading Details (RTD).
- CRO deadlines: Annual return (Form B1), financial statements filing.
- Employer/payroll deadlines: Payroll submissions, employer tax payments, P35 reconciliations.
Your specific dates depend on several factors:
- Business type: Limited companies follow corporation tax rules. Sole traders and partnerships follow income tax rules. The forms and deadlines are different.
- Accounting period: Your company’s financial year end determines when corporation tax is due. Not every business runs January to December.
- VAT frequency: Bi-monthly, quarterly, or annual VAT returns each have their own filing rhythm.
- ROS vs non-ROS: Filing through the Revenue Online Service typically gives you an extended deadline compared to paper filing.
The official Revenue calendar of key dates publishes the exact dates each year. Bookmark it. Build your own calendar from it.
Which Deadlines Apply to Limited Companies?
CRO Annual Return: What Is Your ARD and When Must You File?
Every Irish limited company has an Annual Return Date (ARD) set by the CRO. Your annual return, which includes the Form B1 and financial statements such as the <a href=”#”>income statement</a>, must be delivered to the CRO within 56 days of your ARD.
The annual return is separate from your tax return. It’s a company law obligation, not a tax one. But the consequences of missing it are severe:
- Late filing fees that escalate the longer you delay.
- Loss of audit exemption for the current year and the following year. For small companies, this means paying for a statutory audit that wouldn’t otherwise be required.
- Risk of the company being struck off the register for persistent non-compliance.
File early. Don’t wait until the 56th day. Confirm your ARD at the start of each year and work backwards to ensure your accounts are ready in time.
Corporation Tax (CT1): When Is It Due?
The CT1 return and any balance of corporation tax due must be filed by the 23rd day of the ninth month after the end of your accounting period. For a company with a year end of 31 December 2025, the deadline is 23 September 2026.
Companies that file and pay through ROS may get a short extension beyond the 23rd, depending on Revenue’s published dates for that year. Check the calendar; don’t assume.
The CT1 return requires finalised accounts, tax computations, and (in many cases) iXBRL-tagged financial statements. These take time to prepare, so the real deadline for getting your records to your accountant is months before the filing date.
Preliminary Corporation Tax: When Do You Pay?
Preliminary tax is due during the accounting period, not after it. For most companies, it’s payable by the 23rd of the sixth month before the period ends.
- Small companies (prior year liability under €200,000): One instalment, due by the 23rd of the sixth month.
- Large companies (prior year liability €200,000+): Two instalments. First by the sixth month, second by the eleventh month.
The amount must be at least 90% of the final liability for the current year (or 100% of the prior year for small companies). Underpaying triggers interest from the original due date.
Which Deadlines Apply to Sole Traders and the Self-Employed?
Sole traders and partnerships file income tax, not corporation tax. The system is different. If you’re a tradesman operating as a sole trader, a guide to sole trader tradesman tax Ireland can help you understand how your obligations work.
Income Tax Return (Form 11)
The Form 11 deadline is 31 October following the end of the tax year (which runs January to December). For the 2025 tax year, the deadline is 31 October 2026. ROS filers typically get an extension to mid-November; the exact date is published annually.
Filing and paying are separate obligations. The income tax return and any balance of tax due are both due by the same deadline. Preliminary tax for the following year is also due on this date.
Preliminary Tax for Sole Traders
Self-employed individuals pay preliminary tax for the current year at the same time as filing the prior year’s return. So on 31 October 2026, you’re filing your 2025 return, paying any balance for 2025, and paying preliminary tax for 2026. Getting self-employed tax advice Ireland can help you plan ahead for these overlapping payments.
The preliminary tax must be at least 90% of the final 2026 liability, or 100% of the 2025 liability, or 105% of the 2024 liability (if paying by direct debit). Getting this calculation wrong means interest charges.
What Are the VAT Deadlines in Ireland?
VAT deadlines depend on your filing frequency:
|
Frequency |
Filing Periods |
Deadline |
|
Bi-monthly |
Jan/Feb, Mar/Apr, May/Jun, Jul/Aug, Sep/Oct, Nov/Dec |
23rd of the month following the period end |
|
Quarterly |
Q1 (Jan-Mar), Q2 (Apr-Jun), Q3 (Jul-Sep), Q4 (Oct-Dec) |
23rd of the month following the quarter end |
|
Annual |
Full calendar year |
Varies; typically aligned with income tax deadlines |
ROS filers may get a short extension on certain dates. The VAT deadline covers both filing the return and paying the liability. Late filing attracts interest on any tax due and can trigger Revenue compliance interventions, so understanding the <a href=””>surcharges for late filing Ireland</a> is essential.
Return of Trading Details (RTD)
The annual VAT Return of Trading Details is a separate filing requirement. It summarises your total supplies and purchases for the year. The RTD deadline is typically 23 days after the end of your annual VAT period. Missing it can result in penalties.
When Are Employer Tax Deadlines?
If you have employees, PAYE, PRSI, and USC obligations run on a monthly cycle:
- Payroll submissions: Each time you run payroll, a submission goes to Revenue in real-time under PAYE Modernisation.
- Monthly payment: Employer taxes are due by the 23rd of the month following the payroll month (14th if not filing through ROS). January payroll taxes are due by 23 February.
- Year-end reconciliation: Annual employer returns must be reconciled and submitted after the tax year ends.
Late payroll payments attract interest and can result in compliance action. Revenue is particularly active on employer tax arrears because PAYE and PRSI are amounts deducted from employees’ pay, held in trust.
What Other Deadlines Should Irish Businesses Know About?
- Local Property Tax (LPT): If the business owns property, LPT must be paid by the annual deadline (varies; check Revenue).
- Capital Gains Tax (CGT): Gains realised between 1 January and 30 November are payable by 15 December. Gains in December are payable by 31 January of the following year.
- Relevant Contracts Tax (RCT): Monthly filing for businesses in construction, forestry, and meat processing.
- Tax clearance renewal: If your business requires a tax clearance certificate (for public contracts, licences, grants), monitor its expiry and ensure all filings are current before renewal.
What Happens If You Miss a Deadline?
The consequences vary by obligation but follow a consistent pattern:
- Late filing surcharge: For income tax and corporation tax, a surcharge of 5% (within two months late) or 10% (beyond two months) applies to the tax due.
- Interest: Charged daily from the due date on all late payments across all tax heads.
- Loss of audit exemption: Late CRO annual returns cost you the audit exemption for two years.
- Restricted reliefs: Certain tax reliefs and credits can be restricted if returns are filed late.
- Tax clearance issues: Outstanding filings or payments can prevent you from obtaining or renewing a tax clearance certificate, blocking you from public contracts, grants, and certain licences.
The single most important rule: file on time even if you can’t pay in full. Late filing triggers surcharges on top of interest. Filing on time with a partial payment is always a better outcome than filing late with full payment.
Frequently Asked Questions About Irish Business Deadlines
Does filing through ROS change my deadlines?
Yes. ROS filers typically get an extension beyond the standard deadline. The exact extension varies by tax head and year, and is published on Revenue’s calendar. For most businesses, ROS filing is now mandatory, so the extended deadline is effectively the default.
What’s the difference between filing and paying?
Filing means submitting the return (CT1, Form 11, VAT3, B1). Paying means transferring the money. They’re separate obligations with separate penalties. You can and should file on time even if you can’t pay the full amount due.
How do I keep track of all these dates?
Build a compliance calendar specific to your business. Map your CRO ARD, your corporation tax or income tax dates (based on your accounting period), your VAT cycle, and your payroll payment schedule. Set reminders at least two weeks before each deadline. Share it with your accountant so you’re both working from the same schedule.
What if my accounting period doesn’t match the calendar year?
Your corporation tax deadline is always linked to your accounting period end, not the calendar year. A company with a 30 June year end has a CT1 deadline of 23 March the following year. The calculation is always the 23rd of the ninth month after your period end.
Want a Compliance Calendar Built for Your Business?
Every business has a different combination of deadlines depending on its structure, accounting period, VAT frequency, and payroll schedule. We build tailored compliance calendars for our clients, with reminders, preparation timelines, and accountability, so nothing gets missed. And if you’ve already fallen behind, our backlog bookkeeping service can get everything back on track quickly.
Get in touch today with your company number, accounting year end, and VAT frequency. Not sure about your tax number in Ireland? We’ll help you find it, map every deadline, set the reminders, and make sure you’re always filing on time.
Disclaimer: This guide is for general information purposes only and does not constitute tax advice. Tax rules and thresholds can change. Always consult a qualified accountant or tax adviser for advice specific to your circumstances — and if you’re considering whether to replace your accountant, we have a separate guide to help with that transition.