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Understanding Your Company’s Key Filing Deadlines

Staying on top of your key filing dates for CRO returns and Corporation Tax is essential to remain compliant.

Last updated 16 Apr 2026 | First published 7 Sep 2017

By Gearoid Condon, FCA 5 min read

Limited Companies

Running a company in Ireland comes with a few important annual deadlines. Two of the most important are:
 
  1. Your CRO Annual Return (your company’s legal filing)
  2. Your Corporation Tax Return (your company’s tax filing)
 
Even if you’re not from a financial background, understanding these deadlines will help you avoid penalties, stress and unnecessary audits. Here’s a simple guide to what you need to know.
 

 

1. CRO Filing Date (ARD)

 
Every company must file an annual return with the CRO each year. This return is called a B1 and is separate from your tax return.
 
The deadline date for your return is called your Annual Return Date or ARD. Once your Annual Return Date (ARD) arrives, you have 56 days to file the return. 
 
Your first CRO return is due 6 months after the date of incorporation. No accounts are required with this first return and it’s mainly an administrative filing confirming your company details.
 
Your second CRO Return must be filed 12 months after your first one and then every subsequent 12 months. From your second CRO return onwards the return must include your financial statements. 
 
 

2. Corporation Tax Deadlines (Filing with Revenue)

 
Your Corporation Tax Return (CT1) and payment are due 8 months and 23 days after your year-end.  
 
Companies can choose their own year-end. It is usually the last day of a month.
 
A lot of companies choose the 31st December as their year-end so their financial year aligns with the calendar year. If your year‑end is 31 December 2026, your corporation tax return and payment are due 23 September 2027. Some companies opt for a different year-end date to align their tax return deadline with a quieter period in their business.
 
Although the Corporation Tax Return and payment are due 8 months and 23 days after the year-end, the accounts must be prepared by the second Annual Return Date (ARD), which may fall before the Corporation Tax deadline. In practice, for newly incorporated companies, the first set of accounts must be prepared within 18 months of incorporation, in line with the second ARD.
 
Note that companies must also pay preliminary tax before their year-end. Smaller companies make one payment which is due 1 month before year‑end whereas large companies make two instalments during the year. There is no preliminary tax to be paid in the first year. 
 
 

So how does this all look in practice, here are some examples:

A company that incorporated on 01 January 2026 with a year-end of 31 December 2026:
 
  • 01 Jan 2026: you incorporate your company
  • 01 July 2026: This is your first ARD (6 months after incorporation). From 01 July 2026 you will have 56 days to file your return with the CRO. No company accounts are required at this time. 
  • 31 December 2026: Financial Year-end.
  • 01 July 2027: Your second ARD. You will need to file with the CRO within 56 days and include completed accounts.
  • 23 September 2027: Deadline to file your Corporation Tax Return (CT1) with Revenue and pay the tax liability for 2026. In practice, this return is often completed earlier, typically in July when the CRO return is filed, as the accounts must be prepared by that stage anyway.
  • 31 October 2027: Your director’s Form 11 Tax Return is due. If you file and pay online through ROS then Revenue usually extend this deadline until the middle of November. 
  • 23 November 2027: Preliminary Tax for 2027 due, 1 month before year-end.
 
What can make things more complicated for limited companies is where the year-end is not 31 December. 
 
Here is another example where the year-end is not 31 December:
 
  • 01 April 2026: you incorporate your company
  • 01 October 2026: This is your first ARD (6 months after incorporation). From 01 October 2026 you will have 56 days to file your return with the CRO. No company accounts are required at this time. 
  • 31 March 2027: Financial Year-end
  • 01 October 2027: Your second ARD. You will need to file with the CRO within 56 days and include completed accounts for accounting period 01 Apr 2026 to 31 March 2027.
  • 31 October 2027: Your director’s Form 11 Tax Return is due. If you file and pay online through ROS then Revenue usually extend this deadline until the middle of November. 
  • 23 December 2028: Deadline to file your Corporation Tax Return (CT1) with Revenue and pay the tax liability for accounting period 01 Apr 2026 to 31 March 2027. But as your accounts need to be prepared for you 01 October ARD anyway many companies would just file with Revenue then and not wait until this date to file. 
  • 23 February 2028: Preliminary Tax due for 2028 for accounting period 01 Mar 2027 to 31 March 2028, 1 month before year-end.
 
The TaxAssist App has a Key Dates feature where you can input your own ARD and year-end date, and it will keep track of your key deadlines for you. 
 

 

Accounting periods longer or shorter than 12 months

 
A company doesn’t always have to prepare accounts for exactly 12 months. The CRO allows you to prepare accounts for longer or shorter period, but there are rules.
 
Your first set of accounts can cover up to 18 months from the date the company was set up. After that, you can change your year‑end, but you cannot have a financial year longer than 18 months.
 
If you change your year‑end, your next set of accounts may be shorter (e.g., 6 months) or longer (e.g., 15 months), depending on the new date you choose.
 
If you change your year-end, you may also need to change your ARD so the dates line up.
 
 

What happens if you’re late with your CRO filing?

 
Being late with a CRO return has serious consequences.
 
If you are late twice you automatically lose your audit exemption for two years. This means your accounts must be audited, even if you’re a small company that normally wouldn’t need one. For SMEs, losing audit exemption is the biggest and most expensive consequence.
 
There are also late filing penalties. Penalties of €100 plus €3 per day apply and you run the risk of strike off if filings continue to be missed.
 
 

What should new companies do to be prepared?

 
When new companies are incorporated you should make note of your ARD date. In many cases directors will file this first CRO return themselves as there are no accounts needed.
 
You should appoint an accountant in good time before your 2nd ARD as your accounts will need to be ready for this date. An accountant will usually file your CRO Return and Revenue Corporation Tax return together at this point. 
 
Although there is 18 months between when you incorporate and when first set of accounts are needed it is important to set up a good bookkeeping system so you are not scrabbling for records when the time comes to file. 
 
 

Can TaxAssist Accountants help limited companies?

 
At TaxAssist Accountants we offer a full service for limited companies. We offer bookkeeping services, payroll services, tax planning for growing companies, and we can file your Corporation Tax Return (CT1), CRO Return (B1) and your director Form 11 Tax Return.
 
Contact us today to set up an initial meeting with your local accountant to see what services we can offer you. At the meeting we can give you a fixed fee quote for the services you need. 
 
Remember switching accountant is easy and can be done at any time  of year, you don’t need to wait until after your year-end.
 

Looking for an accountant?

Contact TaxAssist Accountants for a free, no-obligation consultation to get a fixed fee quote

1800 98 76 09

Or contact us

Last updated 16 Apr 2026 | First published 7 Sep 2017

This article is intended to inform rather than advise and is based on legislation and practice at the time. Taxpayer’s circumstances do vary and if you feel that the information provided is beneficial it is important that you contact us before implementation. If you take, or do not take action as a result of reading this article, before receiving our written endorsement, we will accept no responsibility for any financial loss incurred.

Gearoid Condon, FCA

Gearoid is a highly experienced Chartered Accountant with 25 years of expertise in business consultancy, specialising in supporting SME business owners. Gearoid has worked with start-ups and with established businesses to improve the way they run, with particular focus on growth, efficiency, and structuring operations. Through his experience Gearoid has a strong understanding of the tax system and business regulations in Ireland.

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