Key Tax Pay and File Deadlines for 2026

Managing tax compliance effectively requires more than simply meeting filing deadlines.

Understanding when tax liabilities arise and planning ahead for payment and filing obligations can help businesses and individuals avoid unnecessary interest charges, penalties and last-minute compliance pressures.

Below, we outline some of the principal Irish tax payment and filing deadlines relevant to individuals, business owners and companies during 2026 and early 2027.

Capital Acquisitions Tax (CAT)

Capital Acquisitions Tax (CAT) may arise where an individual receives a gift or inheritance.

The key date for CAT purposes is the valuation date. This determines both the value of the gift or inheritance and the deadline for filing any CAT return and paying any CAT liability.

The principal filing deadlines are:

• Valuation dates between 1 January and 31 August: pay and file by 31 October in the same year.

• Valuation dates between 1 September and 31 December: pay and file by 31 October in the following year.

For gifts and inheritances with valuation dates up to 31 August 2026, the filing and payment deadline is extended to 18 November 2026 where the return is filed online and payment is made electronically.

Although the valuation date for a gift is generally the date on which the gift is transferred, determining the valuation date for an inheritance can be more complex and may depend on the administration of the estate.

Importantly, a CAT return may be required even where no CAT is payable. Filing obligations can arise where an individual has received benefits approaching the relevant tax-free threshold or where reliefs such as Agricultural Relief or Business Relief are being claimed.

Capital Gains Tax (CGT)

Capital Gains Tax (CGT) may arise on the disposal of an asset, including a sale, gift or transfer.

CGT operates under a payment regime whereby tax is generally payable before the annual tax return is filed.

For disposals occurring between:

• 1 January 2026 and 30 November 2026, CGT is generally payable by 15 December 2026.

• 1 December 2026 and 31 December 2026, CGT is generally payable by 31 January 2027.

Taxpayers must also report the disposal through the appropriate annual return.

Depending on their circumstances, this may be:

• Form 11;

• Form 12; or

• Form CG1.

Individuals contemplating significant disposals should review potential reliefs in advance, including Retirement Relief, Revised Entrepreneur Relief and Principal Private Residence Relief where appropriate.

Income Tax

For self-assessed taxpayers, the key 2026 filing deadline relates to the submission of the 2025 Income Tax return.

The standard pay and file deadline is 31 October 2026.

Revenue generally provides an extended deadline for taxpayers who both file and pay through ROS. Based on current practice, this deadline is expected to fall on 18 November 2026.

The deadline typically covers:

• Payment of any balance of Income Tax due for 2025;

• Filing of the 2025 Income Tax return;

• Payment of preliminary tax for 2026.

Preliminary Tax

Care should be taken when calculating preliminary tax.

In general, preliminary tax must be at least:

• 90% of the final liability for the current year; or

• 100% of the previous year's liability.

Subject to Revenue conditions, certain taxpayers paying by direct debit may alternatively use the 105% pre-preceding year basis.

Underpayments of preliminary tax can result in interest exposure, even where the final liability is ultimately paid.

Corporation Tax

Corporation Tax obligations depend on a company's accounting period.

In general, a company must file its Corporation Tax return and pay any balance of Corporation Tax due within nine months of the accounting period end, subject to a filing date no later than the 23rd day of that month.

For example, a company with a 31 December 2025 year-end will generally have a filing deadline of 23 September 2026.

Preliminary Corporation Tax

Companies must also ensure that preliminary Corporation Tax payments are made on time.

For large companies with a 31 December 2026 year-end:

• First instalment preliminary tax is generally due by 23 June 2026.

• Second instalment preliminary tax is generally due by 23 November 2026.

Smaller companies generally pay preliminary Corporation Tax in a single instalment, typically due in the eleventh month of the accounting period.

Businesses experiencing significant growth, acquisitions or changes in profitability should review their preliminary tax calculations proactively to minimise exposure to interest and penalties.

Looking Beyond the Main Tax Deadlines

While CAT, CGT, Income Tax and Corporation Tax deadlines are among the most significant annual compliance obligations, they form only part of the wider tax compliance framework.

Businesses may also need to manage ongoing obligations relating to:

• VAT;

• PAYE and payroll taxes;

• Relevant Contracts Tax (RCT);

• Dividend Withholding Tax (DWT);

• Professional Services Withholding Tax (PSWT);

• Stamp Duty; and

• Industry-specific compliance requirements.

Maintaining a tax compliance calendar and reviewing obligations regularly can help reduce compliance risk and avoid unnecessary costs.

How UHY FDW Can Help

At UHY FDW, we assist individuals, entrepreneurs and businesses with tax compliance, planning and advisory services across all major tax heads.

Whether you are preparing for an upcoming filing deadline, managing a significant transaction or seeking clarity on your compliance obligations, our tax team can provide practical and commercially focused advice.

If you would like to discuss your tax obligations or review upcoming filing deadlines, please contact a member of our Tax team.

Get in touch!