If you're considering moving from the United Kingdom to Ireland taxes should be near the top of your planning checklist. Whether you're relocating for work, family, or lifestyle reasons, understanding the tax implications of your move is essential to avoid costly surprises and ensure you're not paying more than you need to.

Ireland and the UK share a common travel area, deep economic ties, and a long history of cross-border migration. But despite these close links, their tax systems differ significantly—from income tax rates and bands to residency rules and allowances. In this expat tax United Kingdom Ireland guide, we'll walk you through everything you need to know for the 2025/2026 tax year, including how to manage the transition year, claim double taxation relief, and optimise your relocation tax planning.

Understanding Tax Residency: When Do You Become an Irish Tax Resident?

The single most important factor in determining your tax obligations when relocating is tax residency. Both the UK and Ireland have their own residency tests, and it's possible—especially in your year of move—to be resident in both countries, one country, or even neither.

Irish Tax Residency Rules

In Ireland, you are considered tax resident if you spend:

  • 183 days or more in Ireland during a single tax year (January to December), or
  • 280 days or more in Ireland over two consecutive tax years, provided you spend at least 30 days in Ireland in each year.

A "day" counts if you are present in Ireland at any time during that day.

Ireland also has the concept of ordinary residence, which applies if you have been resident in Ireland for three consecutive tax years. Once ordinarily resident, you remain so until three consecutive years of non-residence have passed. This affects how your worldwide income is taxed even after you leave Ireland.

UK Tax Residency: The Statutory Residence Test (SRT)

The UK uses the Statutory Residence Test (SRT), which is more complex. It involves three stages:

  1. Automatic overseas test – You are automatically non-resident if you were resident in the UK in none of the previous three tax years and spend fewer than 46 days in the UK, or if you were resident in one or more of the previous three years and spend fewer than 16 days in the UK.
  2. Automatic UK test – You are automatically UK resident if you spend 183 days or more in the UK, or your only home is in the UK.
  3. Sufficient ties test – If neither automatic test applies, your residency depends on the number of "ties" you have to the UK (family, accommodation, work, 90-day presence, country tie) combined with your days spent in the UK.

When you leave the UK partway through a tax year (which runs 6 April to 5 April), you may be able to use split-year treatment to be taxed as a non-resident for the portion of the year after your departure.

The Transition Year Challenge

Because the UK and Irish tax years run on different cycles (UK: 6 April – 5 April; Ireland: 1 January – 31 December), your year of relocation is particularly complex. For example, if you move to Ireland in September 2025:

  • You may be UK resident for 2025/2026 (unless split-year treatment applies)
  • You may become Irish resident for the 2025 tax year if you accumulate 183 days
  • Or you could elect to be treated as Irish resident for 2025 even if you fall short of 183 days

Ireland allows new arrivals to elect for residency from the date of arrival if they can demonstrate they intend to be resident the following year. This can be advantageous for accessing certain credits and reliefs earlier.

Income Tax in Ireland: Rates, Bands, and Credits for 2025/2026

Once you become an Irish tax resident, you'll be subject to Ireland's income tax regime. Here's what you need to know for the 2025 tax year.

Irish Income Tax Rates

Income Band Rate
Up to €44,000 (single person) 20% (standard rate)
Above €44,000 40% (higher rate)

For married couples (one earner), the standard rate band increases to €53,000. For married couples where both spouses have income, the band can extend up to €88,000 (with the increase capped at €31,000 attributable to the second spouse's income).

Additional Irish Charges

Income tax is only one part of the picture. Irish taxpayers also pay:

  • USC (Universal Social Charge): Ranges from 0.5% to 8% depending on income level. For income up to €12,012 the rate is 0.5%, rising through bands of 2% (€12,012–€25,760), 4% (€25,760–€70,044), and 8% above €70,044.
  • PRSI (Pay Related Social Insurance): Typically 4% for employees (Class A), with employer contributions of 11.05%.

When you combine income tax, USC, and PRSI, the effective marginal tax rate for higher earners in Ireland can exceed 52%.

Key Irish Tax Credits (2025)

  • Personal Tax Credit: €1,875 (single) / €3,750 (married)
  • Employee Tax Credit (PAYE Credit): €1,875
  • Earned Income Credit (self-employed): €1,875
  • Rent Tax Credit: €750 per individual / €1,500 per couple

Use our Ireland Income Tax Calculator to estimate your Irish tax liability based on your expected income.

UK Income Tax: What You Still Owe After Leaving

Just because you've moved to Ireland doesn't mean your UK tax obligations end immediately. Depending on your residency status and income sources, you may still owe UK tax.

UK Income Tax Rates (2025/2026)

Income Band Rate
Up to £12,570 (Personal Allowance) 0%
£12,571 – £50,270 20% (basic rate)
£50,271 – £125,140 40% (higher rate)
Above £125,140 45% (additional rate)

Note: The personal allowance tapers at £1 for every £2 earned above £100,000, disappearing entirely at £125,140.

UK Tax on Non-Residents

Even as a non-UK resident, you may still owe UK tax on:

  • UK employment income earned during the UK portion of the tax year
  • UK rental income from property you continue to own
  • UK pension income (though treaty relief may apply)
  • UK dividends from closely-held companies in some circumstances

If you qualify for split-year treatment, only income earned during the UK portion of the year is subject to UK tax. Income earned after your departure date would typically fall outside the UK tax net (except for UK-source income).

Use our United Kingdom Income Tax Calculator to work out your UK tax liability for the portion of the year you remain UK resident.

The UK-Ireland Double Taxation Agreement: Avoiding Being Taxed Twice

One of the biggest concerns for expats is being taxed on the same income by both countries. Fortunately, the UK-Ireland Double Taxation Agreement (DTA) provides mechanisms to prevent this.

How the DTA Works

The treaty assigns taxing rights to one country or the other (or sometimes both, with credit relief) for different types of income:

  • Employment income: Generally taxed in the country where the work is physically performed. If you work in Ireland for an Irish employer, Ireland has primary taxing rights.
  • Pension income: UK government pensions are generally only taxable in the UK. Private pensions may be taxable only in the country of residence (Ireland).
  • Rental income: Taxable in the country where the property is located. UK rental income remains taxable in the UK, but Ireland (as your country of residence) can also tax it—offering a credit for UK tax paid.
  • Dividends and interest: The treaty sets maximum withholding tax rates and determines which country has primary and secondary taxing rights.

Claiming Relief

To avoid double taxation, you'll typically:

  1. Pay tax in the source country (e.g., UK tax on UK rental income)
  2. Declare the income in your country of residence (Ireland)
  3. Claim a foreign tax credit in Ireland for the UK tax already paid

This ensures you pay the higher of the two countries' rates on that income—but not both stacked on top of each other.

Practical Example

Suppose you earn €15,000 in UK rental income (after converting from GBP). You pay UK tax of £2,400 (approximately €2,800) on this income. In Ireland, the same income is taxable at your marginal rate of 40% plus USC, giving an Irish liability of roughly €6,600. You claim a foreign tax credit of €2,800, so your net Irish tax on this income is approximately €3,800. Your total tax paid is around €6,600 — not €9,400.

Remittance Basis: A Key Planning Opportunity for New Arrivals

Ireland offers a valuable tax advantage for new residents known as the remittance basis of taxation. This applies to individuals who are Irish resident but not Irish domiciled.

Who Qualifies?

Most people moving from the UK to Ireland will have a UK or other non-Irish domicile. Domicile is a complex legal concept, broadly meaning the country you consider your permanent home. It is distinct from residency and can remain your country of origin even after years abroad.

How the Remittance Basis Works

If you are Irish resident but not Irish domiciled, you are taxed on:

  • All Irish-source income (fully taxable)
  • All UK/foreign employment income for duties performed in Ireland
  • Foreign income only to the extent it is remitted (brought into) Ireland

This means that investment income, rental income, or other foreign earnings that you keep outside Ireland may not be subject to Irish tax. This is a significant planning opportunity, particularly if you have:

  • UK rental income retained in a UK bank account
  • Investment portfolios held outside Ireland
  • Foreign dividend income

Important Caveats

  • The remittance basis does not apply to UK employment income for duties performed in Ireland—this is fully taxable in Ireland regardless
  • Ireland's domicile levy (€200,000) can apply to individuals with worldwide income exceeding €1 million, Irish-located property worth over €5 million, and an Irish domicile
  • Careful record-keeping is essential to track what funds are remitted to Ireland
  • Changes to the remittance basis regime have been discussed in recent budgets; always check for the latest legislative updates

Practical Steps for Your Relocation Tax Planning

Here is a step-by-step checklist to manage your tax affairs when moving from the UK to Ireland:

Before You Move

  1. Determine your expected departure date and calculate days in each country to understand residency implications for both jurisdictions.
  2. Review your income sources: Separate UK-source, Irish-source, and other foreign income to understand where each will be taxed.
  3. Consider timing: Moving earlier or later in the tax year can significantly affect your residency status and tax liability in both countries.
  4. Maximise UK allowances: Use your full UK Personal Allowance and consider making pension contributions or Gift Aid donations before leaving.
  5. Understand your domicile status: This determines whether you can use Ireland's remittance basis.

During the Move

  1. Register with Irish Revenue: Obtain a PPS number (Personal Public Service Number), which is required for all tax and social welfare interactions in Ireland.
  2. Notify HMRC: Complete form P85 ("Leaving the UK") to inform HMRC of your departure and claim any split-year treatment.
  3. Set up compliant payroll: If starting employment in Ireland, ensure your employer registers you under Ireland's PAYE system.

After the Move

  1. File your UK self-assessment tax return for the year of departure (if required). The deadline is 31 January following the end of the UK tax year.
  2. File an Irish income tax return (Form 11 or Form 12) for the calendar year. The deadline is 31 October of the following year (extended to mid-November for online filing via ROS).
  3. Claim foreign tax credits to avoid double taxation.
  4. Review ongoing UK obligations: UK rental income, pensions, and other UK-source income may require continued UK filing.

Common Mistakes and Misconceptions

Avoid these frequent pitfalls when managing expat tax United Kingdom Ireland obligations:

  • Assuming you're automatically non-UK-resident when you leave: The SRT is complex, and many people remain UK resident longer than expected. Count your days carefully.
  • Ignoring USC and PRSI: Many UK expats focus only on headline income tax rates and are surprised by Ireland's additional charges, which can add 12% or more to the marginal rate.
  • Failing to claim split-year treatment: This is not automatic—you must meet specific conditions and may need to make a claim on your tax return.
  • Remitting foreign income carelessly: If you qualify for the remittance basis, transferring foreign funds to an Irish bank account makes them taxable. Plan your cash flows carefully.
  • Overlooking National Insurance / PRSI implications: Under EU-inherited regulations and bilateral agreements, you should generally only pay social insurance in one country. Obtain an A1/certificate of coverage if necessary.
  • Not updating your tax code with HMRC: Failing to inform HMRC of your departure can result in incorrect tax codes and unexpected liabilities.
  • Missing filing deadlines: With two tax years running on different cycles, it's easy to miss a deadline. Set calendar reminders for both UK and Irish filing dates.

Frequently Asked Questions

Will I lose my UK Personal Allowance when I move to Ireland?

As an Irish resident with UK-source income, you are generally entitled to the UK Personal Allowance (£12,570 for 2025/2026) because Ireland has a double taxation agreement with the UK. However, if your total worldwide income exceeds £125,140, the personal allowance tapers to zero.

Can I contribute to a UK pension from Ireland?

You cannot generally receive UK tax relief on pension contributions once you are no longer a UK taxpayer (except for a basic rate contribution of up to £3,600 gross for five years after leaving). You should explore Irish pension options, which offer generous tax relief at your marginal rate on contributions within Revenue limits.

Do I need to pay Irish tax on my UK state pension?

Under the DTA, UK state pension is generally taxable only in Ireland once you become Irish resident. It is not subject to UK tax. You should inform HMRC to receive it gross (without UK tax deducted).

What happens to my UK ISAs?

UK ISAs lose their tax-free status once you become Irish resident. Any interest, dividends, or gains within the ISA wrapper become taxable in Ireland, even though the ISA remains open. This is a commonly overlooked issue.

How do I calculate my tax if I earn income in both countries?

The best approach is to use country-specific calculators to estimate each liability separately, then apply DTA relief. Start with our United Kingdom Income Tax Calculator for your UK-source income and our Ireland Income Tax Calculator for your Irish-source income.

Conclusion: Plan Early, Save Significantly

Relocating from the United Kingdom to Ireland is one of the more straightforward international moves, given the geographic proximity, Common Travel Area, and strong bilateral agreements. However, the tax implications are far from simple. Differences in tax years, residency tests, and charging structures mean that careful relocation tax planning is essential.

Here are your key takeaways:

  • Determine your tax residency status in both countries for the year of your move—this dictates everything else.
  • Understand the remittance basis: If you're non-Irish domiciled, this can significantly reduce your Irish tax on foreign income.
  • Use the UK-Ireland Double Taxation Agreement to claim relief and avoid paying tax twice.
  • Don't overlook USC, PRSI, and NIC: These additional charges materially affect your net income.
  • File on time in both jurisdictions and claim all available allowances and credits.
  • Use our free tax calculators to model different scenarios before and after your move.

Whether your move is motivated by career opportunities in Dublin's thriving tech sector, family connections, or Ireland's quality of life, getting your tax planning right from the outset will save you time, money, and stress.

This article is for informational purposes only and does not constitute tax advice. Tax laws change frequently; consult a qualified tax professional for advice specific to your situation.