Small businesses play a vital role in Ireland’s economy, providing jobs and driving innovation. As a small business owner, you have important tax obligations to comply with. This report provides an overview of key requirements, deadlines and support available when filing tax returns in Ireland.

Tax Returns

Registering for Tax

  • New companies must register for income tax, VAT, payroll taxes within 30 days
  • Registration done online via Revenue Online Service (ROS)
  • You will receive a tax reference number to use for filing and payments

Key Returns and Deadlines

Income Tax

  • Sole traders file Schedule C and Schedule SE with personal Form 11 tax return 
  • Deadline is October 31 for previous year 


  • VAT returns filed every 2 months
  • Annual VAT return due in August for previous year

Corporation Tax

  • Companies file Form CT1
  • Due within 9 months of year end (Nov 23 for calendar year)
  • Preliminary tax instalments also required 

Penalties and Interest

  • Late filing penalties up to 10% of tax due
  • Restrictions on loss relief claims
  • Interest due at 8% annually on late payments 

Filing Method

  • All tax returns and payments must be filed electronically
  • Use ROS online system for all taxes

Support Available

  • Detailed guidance available on website
  • Recommended to engage with a professional account like Bradán Accountants for advice.

5 Easy Steps for Filing Tax Returns

  • Step 1: File on Revenue Online Service (ROS) 
  • Step 2: Use the pre-populated online Form 11 on ROS 
  • Step 3: Make your self-assessment. 
  • Step 4: Statement of Net Liabilities 
  • Step 5: Send your return to Revenue.

Common Mistakes Small Business Make

Some common mistakes small businesses make when filing Irish tax returns include:

  • Failing to file on time 
  • Not declaring all income such as self-employment, rental, foreign, etc.  
  • Not claiming all available tax credits 
  • Missing deductible expenses like utilities, supplies, contractor fees 
  • Not using a tax advisor or an accountant 

Carefully tracking income and expenses, filing on time, claiming credits, and using a professional can help small businesses avoid costly tax errors.

Key Takeaways

  • Small businesses in Ireland must register for tax and file returns with Revenue Online Service (ROS)
  • Key tax returns include income tax (Form 11), VAT, and corporation tax (Form CT1) with deadlines in April, August, and November respectively
  • Late filing can result in penalties up to 10% of tax due and restrictions on loss relief claims
  • Online filing and payment is mandatory; no paper returns
  • Support is available through Revenue guidance and professional accountants

Learn More : TAX Services


Meeting tax obligations is a key responsibility for Irish small business owners. By registering on time, understanding key deadlines and filing electronically using ROS, businesses can avoid penalties and interest. Support is available from Revenue guidance and professional accountants. The key is staying organized, keeping detailed records and seeking advice when needed.

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