Every year, Irish companies lose their audit exemption, pay avoidable surcharges, and invite Revenue scrutiny for one reason: they missed a filing date. Not because they didn’t know the rules existed, but because the deadlines crept up while they were busy running the business.
The compliance calendar for an Irish business is not simple. Corporation tax, VAT, employer taxes, CRO annual returns: each has its own due date, its own forms, and its own consequences for late filing. This guide pulls them all into one place so you can see exactly what’s coming, when it’s due, and what happens if you miss it.
What Are the Key Filing Deadlines Every Irish Business Needs to Track?
There are four main compliance buckets that most Irish businesses need to manage:
- Corporation Tax (CT): Preliminary tax payments during the accounting period, the annual CT1 return after period end, and any balance due.
- VAT returns: Bi-monthly, quarterly, or annual returns depending on your Revenue setup, each with a combined filing and payment deadline.
- Employer taxes (PAYE/PRSI/USC): Ongoing payroll reporting and payment obligations every time you run payroll.
- CRO Annual Return: A Companies Registration Office filing required from every registered company, tied to your Annual Return Date (ARD).
Your specific deadlines depend on your business type (limited company vs sole trader), your accounting period end date, your VAT frequency, and whether you file electronically through the Revenue Online Service (ROS). Miss any of these and you’re looking at surcharges, interest, loss of audit exemption, or worse.
How Do Corporation Tax Filing and Payment Deadlines Work in Ireland?
Corporation tax is where the stakes are highest for most limited companies. There are three separate obligations to track: preliminary tax, the CT1 return, and the final payment.
Preliminary Tax
Every company must pay preliminary tax during its accounting period. For most companies, preliminary tax is due no later than the 23rd day of the sixth month before the end of the accounting period. So if your accounting period ends on 31 December 2025, your preliminary tax is due by 23 June 2025.
Large companies (those with a corporation tax liability exceeding €200,000 in the prior period) face a different rule. They must pay an initial instalment by the sixth month and a top-up by the eleventh month of the accounting period.
The amount you pay matters too. To avoid interest charges, your preliminary tax must be at least 90% of the final liability for the current period, or 100% of the prior year’s liability (for small companies). Getting this wrong is one of the most common triggers for unexpected interest bills.
The CT1 Return and Final Payment
After your accounting period ends, your company must file its Corporation Tax return (Form CT1) and pay any balance of tax due. The standard deadline is the 23rd day of the ninth month after the end of the accounting period. For a company with a year end date of 31 December, that means 23 September of the following year.
If you file and pay electronically through ROS (which is now mandatory for most companies), you get an extension. Returns filed electronically must be submitted, and tax paid, by the 23rd of the month, but with the ROS extended deadline this can be a few additional days depending on Revenue’s published calendar for that year.
What Happens If You Miss the Corporation Tax Deadline?
- Late filing surcharge: 5% of the tax due if the return is filed within two months of the deadline, rising to 10% after that (capped at specified amounts).
- Interest on late payments: Charged daily from the due date until payment is made.
- Loss of tax clearance: Which can block you from tendering for public contracts, receiving certain grants, or renewing licences.
When Is the Annual Tax Return Deadline for Your Business Type?
The form you file and when you file it depends on whether you’re a limited company or a sole trader.
Limited Companies
Limited companies file a Corporation Tax return (CT1) as described above. The deadline is tied to the end of the accounting period, not the calendar year. If your accounting period doesn’t align with the calendar year, your deadlines shift accordingly.
Sole Traders and Partnerships
Sole traders and partners file an Income Tax return (Form 11). The standard deadline is 31 October following the end of the tax year. The tax year runs from 1 January to 31 December. So for the 2025 tax year, the Form 11 deadline is 31 October 2026. ROS filers get an extension, typically to mid-November.
A common point of confusion: filing and paying are separate obligations. You should always file your return on time even if you can’t pay the full liability. Filing late triggers a surcharge on top of whatever you already owe. Filing on time but paying late means you face interest, but not the surcharge.
What Is the CRO Annual Return Deadline and When Do Companies Have to File?
Every company registered in Ireland must file an annual return with the CRO. This is separate from your tax returns. The filing date is driven by your Annual Return Date (ARD), which is set when the company is incorporated.
The annual return must be delivered to the CRO within 56 days of your ARD. So if your ARD is 1 June, your filing deadline is 27 July. The return itself includes the annual return form (B1) plus financial statements where required.
This deadline is critical for several reasons:
- Late filing fees: The CRO charges penalties for late returns, and these add up quickly.
- Loss of audit exemption: If a company’s annual return is filed late, it loses its entitlement to the audit exemption for that year and the following year. For a small company, this means paying for a statutory audit that wouldn’t otherwise be required, often costing several thousand euro.
- Enforcement risk: Persistent non-compliance can lead to the company being struck off the register.
Practical advice: confirm your ARD early each year. Don’t wait until accounts are finalised to think about it. Align your accounts preparation timetable with the ARD, not just your financial year end. If you need to, you can file your annual return on time with unaudited accounts and upload the financial statements once they’re ready, as long as they’re filed within the allowed window.
If you’re unsure of your ARD or need to change it, you can check CRO online or contact the CRO helpdesk.
What Are the VAT Deadlines in Ireland and How Often Do You Need to File?
VAT filing frequency varies by business. Most Irish companies file bi-monthly VAT returns. Others file quarterly or annually, depending on their turnover and Revenue’s assignment.
Each VAT return has a combined filing and payment deadline. For bi-monthly filers, the return and payment are due by the 23rd of the month following the end of the VAT period. For example, the January/February VAT return is due by 23 March. ROS filers may get a short extension on certain dates.
Common last-minute problems that cause late VAT filing:
- Missing purchase invoices that haven’t been entered into the system.
- Incorrect VAT rates applied to transactions (particularly on mixed supplies or reverse charge scenarios).
- Confusion between cash basis and invoice basis accounting, which affects when VAT is due.
- Waiting for bank reconciliation to be completed before preparing the return.
Missing a VAT deadline means interest on late payments and the risk of Revenue compliance interventions. VAT is one of the tax heads where Revenue is most active in pursuing arrears, because it’s money you’ve already collected from customers on their behalf.
When Are Employer Taxes Due and What Must Employers File?
If you have employees, you have ongoing PAYE, PRSI, and USC obligations. Under PAYE Modernisation, employer reporting is now real-time: each time you run payroll, you submit a payroll submission to Revenue electronically.
Payment of employer taxes is due by the 23rd of the month following the payroll month (14th if not paying electronically, though nearly all employers now use ROS). So January payroll taxes are due by 23 February.
The most common triggers for late employer tax payments:
- Payroll processing delays (staff holidays, system issues, waiting for timesheets).
- Incorrect employee setup in the payroll system leading to wrong deductions.
- Cash flow shortfalls, particularly in seasonal businesses where revenue dips but payroll obligations continue.
Controls that help: set a fixed payroll calendar with backup processors, use direct debit or scheduled ROS payments, and keep a dedicated account for tax funds so they’re not mixed with operating cash.
What Are the Consequences of Missing Business Filing Deadlines in Ireland?
The penalties vary by tax head and obligation, but the pattern is the same: the longer you leave it, the worse it gets.
|
Obligation |
Late Consequence |
|
Corporation Tax (CT1) |
5-10% surcharge on tax due, daily interest, restricted tax clearance |
|
Preliminary Tax |
Interest from the original due date until payment |
|
VAT returns |
Interest on late payments, compliance interventions |
|
Employer taxes (PAYE/PRSI/USC) |
Interest, penalties, potential prosecution for persistent default |
|
CRO Annual Return |
Late filing fees, loss of audit exemption (current + following year), strike-off risk |
|
Income Tax (Form 11) |
Surcharge, interest, restricted access to certain reliefs |
Beyond the financial penalties, late compliance creates operational problems. Banks check tax clearance before approving loans. Public procurement contracts require tax compliance certificates. Grant agencies verify CRO filings before releasing funds. Suppliers and partners run company checks. Being non-compliant doesn’t just cost you money in penalties; it can cost you business.
What Should You Do If You Can’t Pay Your Tax Liability on Time?
First, file on time regardless. A filed return with an unpaid balance is a better position than an unfiled return with an unpaid balance. The surcharge for late filing is on top of the interest for late payment. Don’t double the problem.
Second, quantify the liability as early as possible. Don’t wait until the deadline to discover you owe more than expected. Monthly management accounts and rolling tax forecasts catch shortfalls early, when you still have options.
Third, engage with your accountant and, if necessary, with Revenue. Revenue has mechanisms for managing tax debt, but they expect you to come forward proactively rather than ignore the problem. Document your cash flow position and be realistic about what you can pay and when.
Prevention is better than cure. The businesses that rarely face this problem are the ones that:
- Set aside VAT and PAYE in a dedicated savings account as it’s collected, so it’s never mixed with working capital.
- Run quarterly tax forecasts so there are no surprises at year end.
- Use monthly management accounts to spot cash flow issues before they become tax payment issues.
Frequently Asked Questions About Filing Deadlines in Ireland
What’s the difference between filing and paying tax?
Filing means submitting the return (CT1, VAT3, Form 11, B1). Paying means transferring the money to Revenue or the CRO. They’re separate obligations with separate penalties. You can and should file on time even if you can’t pay in full. Late filing triggers a surcharge. Late payment triggers interest. Don’t incur both.
Do filing deadlines change if you use ROS?
Yes. Companies that file and pay electronically through the Revenue Online Service typically get an extension of a few days beyond the standard deadline. The exact dates are published by Revenue each year. For most businesses, ROS filing is now mandatory, so this is effectively the default deadline. Check Revenue’s calendar of key dates for the current year’s specific dates.
What deadlines apply to small companies vs large companies?
The main difference is in preliminary corporation tax. Small companies (prior year CT liability under €200,000) pay one instalment by the 23rd of the sixth month. Large companies pay two instalments. CRO filing deadlines are the same regardless of company size, though the audit exemption threshold determines whether financial statements must be audited.
What happens if I miss my CRO Annual Return Deadline?
Late filing fees apply immediately. More significantly, the company loses its audit exemption for the year the return is late and the following year. For small companies, this is an expensive consequence: a statutory audit can cost thousands of euro that wouldn’t be needed if the return had been filed on time within 56 days of the ARD. Act quickly if you’ve missed it; the sooner you file, the lower the total cost.
Where can I check the official Revenue deadline calendar?
Revenue publishes a calendar of key dates each year covering all tax heads. Bookmark it, set reminders in your calendar for each deadline, and share it with your accountant so you’re both working from the same schedule.
Want Help Staying on Top of Your Filing Deadlines?
The businesses that never worry about deadlines are the ones with a system: a compliance calendar mapped to their specific year end, VAT frequency, payroll schedule, and ARD. They know what’s due, when, and who’s responsible for it.
We build that system for our clients. A tailored deadline schedule, quarterly compliance check-ins, and proactive reminders so nothing slips. If you’re spending mental energy trying to remember what’s due next, that’s energy better spent on the business.
Get in touch today to get a deadline map built for your company. Have your company number, accounting year end date, VAT frequency, payroll schedule, and ROS access status ready, and we’ll have your compliance calendar set up quickly.
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.