Two things changed for British people moving to Portugal, and neither of them is the one most guidance leads with. Brexit changed the immigration route and left the tax test alone. The domicile system, which most pre-2025 UK expat writing is really about, was abolished. Anything written before 2025 describing the remittance basis is describing a system that no longer exists.
Two residency tests, and they can both say yes
The Portuguese test is CIRS art. 16: more than 183 days in Portugal in any 12-month period, or a home kept here in conditions implying you mean to hold it as your habitual residence. Residence starts on the first day of the stay and ends on the last day of presence.
The UK test is the Statutory Residence Test, and it does not resemble that at all. HMRC's own summary is that you are UK resident if you meet one or more of the automatic UK tests or the sufficient ties test, and you do not meet any of the automatic overseas tests. The order is part of the test: running the ties test on somebody who already meets an automatic overseas test produces a wrong answer.
| If you were UK resident in | You are automatically non-resident below |
|---|---|
| 1 or more of the previous 3 tax years | 16 UK days |
| None of the previous 3 tax years | 46 UK days |
Split-year treatment applies automatically where its conditions are met. There is no application to HMRC and therefore no election to forget — but eligibility is checked before you leave and again at the end of the year, which implies it can be lost in between. One trap sits inside it: dividends paid to a non-resident during a split year cannot be treated as excluded income and are taxed in the UK in full, so a dividend timed around a move can be timed exactly wrong.
Which UK convention is in force
Portugal and the United Kingdom signed a new convention in London on 15 September 2025. The Assembleia da República approved it by Resolução n.º 206-A/2025, published in the Diário da República of 29 December 2025. It replaces the 1968 convention outright.
That matters less than it sounds for most people, because the two texts put pensions in the same two articles and reach the same answer in the ordinary case. It matters a great deal in one case, and that case is below.
Pensions — the part worth getting right
Article 17 of the 2025 convention: pensions and other similar remuneration paid to a resident of a contracting state may be taxed only in that state, subject to article 18(1). So a UK pension paid to somebody resident in Portugal is Portugal's to tax — the private one, the occupational one and the State Pension alike.
Article 18(1) is the exception, and it is narrow. Salaries, wages, pensions and similar remuneration paid by a contracting state for services rendered to that state are taxable only in the paying state. A UK civil-service, armed-forces or other government-service pension therefore stays with the UK.
| Pension | Taxed by | Article |
|---|---|---|
| State Pension | Portugal | art. 17 |
| Occupational or personal pension | Portugal | art. 17 |
| Government-service pension, UK national | UK only | art. 18(1) |
| Government-service pension, Portuguese national | Both states may tax | art. 18(1) |
The 25% lump sum is a UK rule, not a treaty rule
A quarter of a UK pension can normally be taken tax free at retirement age. That is UK domestic law. The convention gives the taxing right over the pension to the state of residence, and Portugal has no matching exemption written into the CIRS.
Leaving the UK, and going back
HMRC is described as scrutinising departures more closely than at any point in the past decade, and the mechanism is the ties, not your intention. A UK home still available, family still in London and flight records showing 50 UK days is a family tie, an accommodation tie, a work tie and probably a 90-day tie — and it does not matter what you meant to do.
Portugal has an anti-avoidance rule of the same shape pointing the other way. Under CIRS art. 16 n.º 14 you stay Portuguese-resident for the whole year in which you lose residence, where you spent more than 183 days here that year and afterwards received income that would have been taxable had you stayed. Art. 16 n.º 16 catches somebody who leaves and regains Portuguese residence during the following year — they are treated as resident for that whole year. A person leaving Portugal for the UK can be inside both countries' rules at once.
Relief, and the annexes
Article 21 of the 2025 convention gives Portugal's relief as an ordinary credit: Portugal deducts an amount equal to the UK tax paid, capped at the fraction of Portuguese tax attributable to that income. That lines up with CIRS art. 81 — the lesser-of credit, with unused credit carried forward five years and no refund where the UK charged more than Portugal would have.
| Income | Ceiling | Article |
|---|---|---|
| Dividends, general | 10% of gross | art. 10(2)(a) |
| Dividends paid out of income from immovable property | 15% of gross | art. 10(2)(b) |
| Interest | 10% of gross | art. 11 |
| Royalties | 5% of gross | art. 12 |
On the Portuguese return, UK income and the UK tax paid on it go in Anexo J, and any account held outside Portugal goes in quadro 11 of the folha de rosto with no income threshold — a dormant account and an account you can merely operate both count. The filing window is 1 April to 30 June, and 30 June applies whether or not it falls on a business day.
Does Portugal tax my UK State Pension?
Yes. Article 17 of the 2025 Portugal–UK convention gives pensions and similar remuneration to the state of residence alone, subject only to the government-service exception in article 18(1). A State Pension is not a government-service pension.
What about my UK civil-service or armed-forces pension?
Article 18(1) keeps it with the UK — unless you are a Portuguese national and not a UK national, in which case the convention allows both states to tax it. Nationality, not residence, decides that case.
Is my 25% tax-free lump sum still tax free if I live in Portugal?
The 25% is UK domestic law, and the convention gives the taxing right over pensions to the state of residence. Our sources do not settle how AT characterises the lump sum, so this is the item to get advice on before drawing it rather than after.
Which Portugal–UK treaty applies right now?
A new convention was signed on 15 September 2025 and approved by Resolução da Assembleia da República n.º 206-A/2025 on 29 December 2025. It enters into force on the last diplomatic notification and takes effect in Portugal from the 1 January after that. We hold the approval but not the notification date, so ask before relying on one text rather than the other.
Can I be tax resident in both the UK and Portugal?
Both countries can find you resident under their own rules, which are completely different tests. The convention then has a tie-breaker to allocate you to one of them for treaty purposes. Being caught by both domestic tests is common; it is not the end of the analysis.
Does the remittance basis still work?
No. The domicile-based system and the remittance basis were abolished from April 2025, and liability rests on residence. Guidance written before then is describing a system that no longer exists.
If I move back to the UK within five years, does that undo anything?
It can. Returning within five complete tax years lets HMRC tax certain income and gains received while you were non-resident as if they had been received while UK resident. Portugal has its own version pointing the other way, in CIRS art. 16 n.os 14 and 16.