Moved between Ireland and the UK this year? Split-year tax residence, explained

If you moved to or from Ireland this year — for a job, a partner, or just to come home — you probably assume you'll be taxed as a full resident of wherever you now live, for the whole year. That's not automatic. Both Revenue and HMRC allow a tax year to be split into a resident part and a non-resident part around your move date, so you're not taxed on your worldwide income for months you weren't actually living there. The catch: Ireland's rules and the UK's rules run on completely different logic, and the two countries' tax years don't even start on the same day.

What is split-year tax residence?

Split-year treatment stops you being taxed as a full-year resident of a country you only lived in for part of the tax year. Instead of your whole year's worldwide income falling into scope, the year is divided into a resident part — taxed in the normal way — and a non-resident part around the date you moved, which is generally taxed only on income actually sourced in that country.

Without it, moving countries mid-year can mean a tax office treats income you earned entirely abroad, before you ever arrived, as part of your taxable year. For cross-border movers between Ireland and the UK — a routine move, not an exotic one — this is worth understanding before you file anything.

How does Ireland decide if you're tax resident?

You're Irish tax resident for a year if you spend 183 days or more in Ireland in that tax year, or 280 days or more combined across the current and previous tax year. A "day" counts if you're in Ireland for any part of it, with narrow exceptions for being airside at an airport awaiting a connection, or delayed by something outside your control.

Ireland's tax year runs 1 January to 31 December, which matters when you're comparing your position to the UK side — see below.

Moving to Ireland mid-year: how split-year treatment works

You can claim split-year treatment in your year of arrival if you're resident in Ireland that year but weren't resident the year before. Employment income you earned abroad before your arrival date is disregarded for Irish tax, you get full tax credits for the year, and the relief applies to employment income only — not rental, investment or pension income.

For moves after 31 December 2024, Finance Act 2024 changed the process: you now self-assess your eligibility and claim the relief directly in your Irish Income Tax Return, rather than applying separately. For earlier moves, the claim was made in writing — either through MyEnquiries in myAccount or by letter to Revenue.

Leaving Ireland mid-year: how split-year treatment works

You can claim split-year treatment in your year of departure if you're resident that year but intend to be non-resident the following year, and you're leaving permanently to take up employment abroad. You get full tax credits for the year, and employment income earned abroad after your departure date is ignored for Irish tax.

As with arrivals, moves after 31 December 2024 are self-assessed in your Income Tax Return. You'll typically need to show proof of the move — an employer's statement or your employment contract — confirming when the foreign employment started.

Moving to or from the UK: the Statutory Residence Test

The UK uses the Statutory Residence Test (SRT) rather than a simple day count. Spending 183 or more days in the UK in a tax year makes you automatically resident; spending fewer than 16 days (or fewer than 46 if you weren't UK resident in any of the previous three tax years) makes you automatically non-resident. Between those extremes, a "sufficient ties" test weighs things like family, accommodation and work in the UK against your day count.

If you're UK resident for the year under the SRT, you then check whether one of HMRC's eight split-year "cases" applies — Cases 1 to 3 cover leaving the UK (for example, starting full-time work abroad or ceasing to have a UK home), Cases 4 to 8 cover arriving (for example, starting full-time UK work or starting to have your only home in the UK). You need to meet every condition of a case for it to apply, and if more than one could apply, priority rules decide which one does. The full conditions are set out in HMRC's RDR3 guidance.

Split-year treatment under the SRT isn't a separate application — if you qualify, it applies automatically. But you still have to identify and report it, on the SA109 "Residence, remittance basis etc" supplementary pages of a Self Assessment tax return.

Why the two countries' tax years catch people out

Ireland's tax year is the calendar year, 1 January to 31 December. The UK's tax year runs 6 April to 5 April. A single house move — say, relocating in September — falls in the same half of each system, but a move in February or March can land in different tax years on each side, so your Irish and UK positions may need working out separately and won't necessarily "split" on the same date.

This mismatch is the part generic UK or Irish tax guidance rarely covers, because it only bites people moving specifically between these two systems. If you're unsure which side of a tax-year boundary your move falls on in each country, work it out for Ireland and the UK independently rather than assuming one answer covers both.

What about being taxed twice?

Ireland and the UK have a double taxation agreement that generally prevents the same income being taxed twice in both countries. Split-year treatment reduces the risk in the first place by narrowing each country's taxing period to the part of the year you actually lived there — but if you do end up assessed in both, the treaty's relief provisions are the mechanism to resolve it, not something that happens automatically without you claiming it.

How do you actually work this out — step by step

Common questions

This guide is general information, not tax advice. Residence rules are fact-specific and change — always confirm your own position with Revenue, HMRC and, where both countries could tax the same income, the Ireland–UK double taxation agreement, before you file.

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