The New UK-Portugal Tax Treaty (2026): What British Founders and Remote Earners Actually Pay

If you are a British founder or remote earner who has moved, or is about to move, to Portugal, the updated UK-Portugal double-tax treaty decides which country gets first claim on each slice of your income, but it does not, by itself, set your final bill. The treaty was signed in London on 15 September 2025, entered into force on 29 December 2025, and applies from 1 January 2026 for Portuguese taxes and withholding, from 1 April 2026 for UK Corporation Tax, and from 6 April 2026 for UK Income Tax and Capital Gains Tax. It caps cross-border withholding (dividends at 10%, with a 0% tier that only a company beneficially owning at least 10% of the payer for at least 12 months can reach, not a founder holding the shares personally; interest at 10%, or 5% for banks; royalties at 5%), it gives gains on ordinary company shares exclusively to your country of residence, and for companies it resolves dual residence by a mutual-agreement procedure between the two tax authorities rather than an automatic switch to wherever the company is managed. What it does not do is override each country's own rules on how it taxes the income the treaty assigns to it. That is why two British founders on identical dividends can pay very different amounts: one lands inside Portugal's IFICI regime, the other on the standard scale. The treaty is the traffic-light system; IFICI or the ordinary Portuguese rates are the actual toll. Everything below reads the treaty from a founder's and remote earner's point of view, not the retiree-and-pension framing most write-ups default to. None of it is tax advice, and every specific figure should be confirmed against the GOV.UK treaty text and with a cross-border adviser for your own facts.

What the new treaty changed, and what it didn't

Portugal and the UK had been operating under a convention in force for over five decades, and it was showing its age. The 2025 instrument replaces it with a modern, OECD-model-aligned text: updated definitions, an anti-abuse clause in Article 27, and, importantly for owner-managers, a company-residence tie-breaker rebuilt as a mutual-agreement procedure. For a person moving between the two countries, the practical changes are less dramatic than the timing suggests. The treaty still does three familiar jobs. It decides your residence when both countries claim you. It allocates taxing rights over each type of income, dividends, interest, royalties, employment income, business profits, capital gains and pensions. And it tells each country how to relieve double taxation on what is left, generally by giving a credit for tax paid in the other state.

One article is genuinely new rather than modernised. The 2025 text lets the country where property sits tax the gain on shares that derive more than 50% of their value from immovable property there, tested at any point in the 365 days before the disposal. The 1968 convention had no such rule. If your company's value is mostly Portuguese or British bricks rather than trade, that article is now in play on a sale.

What the treaty is not is a relocation plan or a rate cut. It does not make your income "UK-only" because your company is British, and it does not make it "Portuguese and exempt" because you have an IFICI card. It sets the boundaries; your domestic position on each side fills them in. Keep that separation in mind and most of the confusion around this treaty disappears.

Which treaty governs the return you are filing now

Before you read a single new article number, check which convention actually applies to the year in front of you. The staggered commencement dates are not decoration. Because the new text takes effect for UK Income Tax and Capital Gains Tax only from 6 April 2026, and for Corporation Tax from 1 April 2026, the 1968 convention governed UK income tax and CGT for the whole of the 2025/26 tax year and corporation tax up to 31 March 2026. Anyone completing a 2025/26 UK return in the next few months is reading the old treaty, not this one. That matters commercially, because the old dividend article capped source-country tax at 10% and 15% and contained no 0% tier at all, so a structure built to reach the new exemption gives you nothing for a payment that fell in the earlier period. HMRC's own manual sets the commencement dates out by tax; check yours there before you assume "the new treaty" covers the transaction you are worried about.

The first question the treaty answers: which country is your tax home

Before any dividend or salary rate matters, the treaty has to decide where you are resident, because a treaty rate only helps once it is clear who is the "source" country and who is the "residence" country. When you live in Portugal but keep UK ties, both countries can treat you as resident under their own domestic tests. That is the moment the tie-breaker in the residence article does its work.

For individuals the treaty uses the standard ladder found in modern conventions, applied in order until one step decides it:

1. Where you have a permanent home available to you.
2. If you have one in both countries, where your centre of vital interests lies, that is, where your personal and economic ties are stronger.
3. If that is unclear, where you habitually stay.
4. If still unresolved, your nationality.
5. Failing all of that, the two tax authorities settle it by mutual agreement.

The practical lesson for founders is blunt: keeping a UK address, a UK phone number or a UK company does not, on its own, keep you UK-resident once your actual life, your home, your family, your day-to-day work, has moved to Lisbon or Porto. The ladder looks at substance. Do not assume you can be "still UK tax-resident" for convenience while living full-time in Portugal; confirm your residence position with a cross-border adviser, because it drives everything that follows. Companies get a different and far harsher mechanism, covered further down.

Dividends: the number most founders get wrong

Here is the figure that circulates in founder chats: "the treaty caps UK dividends at 10%, and 0% if you own more than 10% of the company." That is nearly right, and the three things it leaves out are the ones that matter.

Start with the article itself. Article 10(2) caps the source country's withholding tax on dividends at 10% of the gross amount, with a higher 15% ceiling for dividends paid out of immovable-property income by an investment vehicle that distributes most of that income annually and is itself exempt on it. The 0% tier sits separately, in Article 10(3), and it is written company-to-company. Dividends are taxable only in the recipient's state where the beneficial owner is a company resident in the other state that holds directly at least 10% of the capital of the paying company for an uninterrupted period of at least one year containing the date the dividend is paid, and where each company is liable to corporate tax without enjoying a general exemption from it.

That wording is the first omission, and it is the one that matters most to a founder. If you hold your UK Ltd shares in your own name you are an individual, not a company, so Article 10(3) does not reach you however large your stake. You sit on the 10% general cap in Article 10(2). The 0% tier is built for corporate structures: a holding company that owns 10% or more of the trading company and has held it for the qualifying 12 months.

The second omission is that holding period, which catches the corporate case too. A stake topped up to 10% last month does not qualify, and the qualifying year has to contain the payment date. The third omission is direction. These are limits on what the source country may withhold. For a British founder living in Portugal and drawing dividends from a UK limited company, the source country is the UK, and the UK charges no withholding tax on ordinary company dividends paid to a non-resident shareholder. So for the standard case the practical answer survives the correction intact: your UK trading-company dividends leave Britain untaxed at source either way, and the treaty cap removes a tax that was not being charged in the first place.

There is one real exception, and it is the reason Article 10(2)'s 15% tier exists at all. Property income distributions from a UK REIT or a Property Authorised Investment Fund are withheld at 20%, rising to 22% from 6 April 2027. If part of your portfolio sits in UK property funds, that is live withholding on a real payment, and the treaty ceiling on it is a number you can actually use.

Interposing a holding company is exactly what Article 27 is aimed at

Read the 0% tier and the obvious move suggests itself: put a company between you and the trading company, hold 10% or more for a year, collect the exemption. Article 27 is the reason to slow down. The convention's entitlement-to-benefits article denies a benefit where, having regard to all relevant facts and circumstances, it is reasonable to conclude that obtaining that benefit was one of the principal purposes of the arrangement, unless granting it would accord with the object and purpose of the relevant provisions. A holding company inserted into a founder's structure whose main visible effect is to convert a 10% ceiling into a 0% ceiling is the textbook case that test was drafted for. The rule does not forbid holding companies; it forbids holding companies whose purpose is the treaty rate. If there is a real commercial reason for the structure, document it at the time, not in correspondence three years later.

The bill that actually matters is the Portuguese one

Portugal is now your residence country and taxes your worldwide income. What you pay there is decided not by the treaty but by your Portuguese regime:

• On the standard scale, foreign dividends received by a Portuguese resident are generally taxed as investment income (category E) at a flat 28% under the CIRS, with an option to aggregate them into the progressive scale if that works out better. The rate rises to 35% where the payer sits in a jurisdiction on Portugal's blacklist.
• Under IFICI, most foreign-source income, dividends included, is generally exempt in Portugal, counted only to set the rate applied to your other income (the "with progression" mechanism). See our IFICI vs the Beckham Law comparison for how that exemption is structured and where its edges are.

So the honest headline is the opposite of the chat-group version: the treaty does not give you 0% on your UK dividends because the UK was not taxing them anyway; IFICI, if you qualify for it, is what can shelter them on the Portuguese side. Whether dividends from a company you also work in and control sit cleanly inside IFICI's foreign-income exemption is exactly the kind of fact-sensitive question to put to a Portuguese tax adviser before you rely on it.

Moving to Portugal and unsure how your UK income will actually be taxed? Relovisa runs the Portugal D3 and Portuguese-payroll routes into IFICI as a single engagement, and models the tax outcome before you file, so the immigration plan is built to carry the tax position, not fight it. Talk to us about Portugal D3 + payroll →

Interest, royalties and other passive income

Interest follows a similar logic to dividends but with a different ceiling. The treaty caps source-country withholding on interest at 10%, reduced to 5% for interest paid to a regulated bank and 0% for interest paid to a government or central bank. Again, whether that cap does any work depends on which way the money flows and what each country's domestic law would otherwise charge. On the Portuguese residence side, interest is ordinarily taxed like other investment income on the standard scale, or generally exempt under IFICI's foreign-income treatment.

Royalties have their own ceiling and it is worth knowing, because founders who license software, brand or IP across the two countries hit it constantly. Article 12(2) caps source-state tax on royalties at 5 per cent of the gross amount where the beneficial owner is a resident of the other state. That is a genuine limit on what the payer's country may take before the money reaches you, and it is one of the few places in this treaty where the cap does visible work for an individual. Check the definition of royalties in the article against what your contracts actually pay for, because service fees, licence fees and mixed contracts are treated differently and the label on the invoice does not decide it.

Salary and remote-work income

For remote earners the relevant rules are the ones on employment income and business profits, not dividends. As a general principle under the treaty, employment income is taxable where the work is physically performed, subject to the usual short-stay exception for brief periods spent working in the other country under a foreign employer. If you live in Portugal and do your job from a desk in Portugal, Portugal is where that salary is taxed, even if your employer is a UK company and pays you in sterling into a UK account. The location of the payer and the currency do not move the taxing right; the location of the work does.

That has two consequences British remote earners routinely underestimate. First, a UK employer paying you while you sit in Portugal can create UK payroll and Portuguese tax and social-security questions at the same time, which is one of the reasons a local employment structure often ends up cleaner than "keep me on UK payroll and I will sort my own Portuguese tax." Second, self-employed founders invoicing UK clients from Portugal are, as a rule, taxed in Portugal on that work, and may fall inside IFICI's 20% flat rate if their activity is on the qualifying list. For how the D3 and payroll routes handle exactly this "paid from abroad, living in Portugal" situation, see our guide to the Portuguese employer-of-record route and the D3 versus D8 comparison.

One distinction to keep clean: social security is not tax, and the treaty does not touch it. Which country's system you contribute to is settled by the UK-EU Trade and Cooperation Agreement's Protocol on Social Security Coordination, and HMRC still issues an actual A1 certificate under it, the same document by the same name as before Brexit, not a domestic equivalent. That certificate can legitimately leave you paying National Insurance in one country while you are plainly tax-resident in the other. Founders conflate the two constantly. Ask about the tax position and the contributions position as two separate questions.

Where IFICI meets the treaty: the founder's actual bill

This is the section the retiree-framed articles skip. For a working founder, the treaty and IFICI operate on two different levels, and you need both to read your outcome.

The treaty decides which country may tax each income type and caps the source country's rate. IFICI then decides how Portugal taxes what the treaty assigns to it. Put the two together and a British founder inside IFICI typically sees:

• Qualifying Portuguese-source employment or self-employment income taxed at a flat 20% for 10 years, with no upper ceiling, provided the role sits on IFICI's list of highly qualified and research-and-innovation activities.
• Most foreign-source income (including, as a general rule, dividends and interest from a UK company) generally exempt in Portugal under IFICI, counted only to set the rate on other income.
• Foreign pensions as the standout exception, taxed at the normal progressive rates rather than exempt, a deliberate change from the old Non-Habitual Resident regime. For 2026 those rates start at 12.5% on the first €8,342 of taxable income and reach 48% above €86,634, with a solidarity surcharge of 2.5% on income over €80,000 and 5% over €250,000 taking the top marginal rate to roughly 53%. NHR itself closed to genuinely new entrants from 1 January 2024 under Lei n.º 82/2023; the 31 March 2025 date that still circulates was only the deadline for a transitional cohort who already met the 2023 pre-conditions, such as an employment contract or residence visa in place before the end of 2023. If you are moving now, NHR is not an option and IFICI is the question.

IFICI has hard edges a founder must respect. It is gated to a defined activity list, so a contract that reads as a generic "consultant" or "manager" can fall outside it even when the work is genuinely technical. And it has a registration deadline of 15 January of the year after you first become a Portuguese tax resident. Missing that date does not destroy your access to the regime outright: the Autoridade Tributária's own IFICI FAQ says that where the inscription is filed outside the deadline, IFICI takes effect from the year in which the inscription is made and runs for the remainder of the legal period. The trap is what that sentence does not give you. The ten-year window is anchored to your first year of Portuguese tax residence, not to your paperwork, so a late filing buys you nothing at the far end. Every year you file late is a year taxed on the standard scale and a year of relief gone for good, which is precisely the point our guide to the 15 January IFICI application deadline makes: no retroactive applications, no individual extensions, and a lost first year permanently shortens your run. The eligibility map, activity codes and the visa most founders use to reach IFICI are covered in our Portugal D3 + IFICI eligibility guide.

Why the retiree framing misleads founders

Most coverage of a new UK-Portugal treaty is written for pensioners, because pension income is where the old treaty and the NHR regime produced the famous low-tax outcomes. That framing actively misleads founders on two points. First, pensions are now one of the few income types IFICI does not shelter, so the "Portugal is a tax haven for your retirement" story is weaker than it was even for its original audience. Second, a founder's income is dividends, salary and business profits, none of which behave like a pension under either the treaty or IFICI. If your mental model of the treaty comes from a retirement-planning article, you will reach for the wrong article numbers and the wrong Portuguese regime. Read your own income types on their own terms.

Selling the company: Article 13(5) is the sentence to know

For a founder with an exit in view, the single most valuable line in this treaty is the residual rule at the end of the capital gains article. Article 13(5) reads: "Gains from the alienation of any property other than that referred to in paragraphs 1, 2, 3 and 4, shall be taxable only in the Contracting State of which the alienator is a resident." Read that against your own facts. Shares in an ordinary trading company are not immovable property, not business property of a permanent establishment, not ships or aircraft. They fall into paragraph 5. So a British founder who is genuinely tax-resident in Portugal at the moment of sale, selling a UK company that is not land-rich, hands exclusive taxing rights to Portugal and the UK is denied a charge under the treaty.

Three qualifications keep that from being a free lunch. The first is Article 13(2): if more than 50% of the share value derives from UK immovable property at any point in the 365 days before the disposal, the UK can tax the gain, and a founder whose company owns its premises should test that before assuming otherwise. The second is Article 27, which sits over the whole convention: moving residence for the purpose of collecting Article 13(5) on a sale already in progress is precisely the fact pattern a principal-purpose test is designed to catch. The third is the one that actually bites most often, and it is not in the treaty at all: the UK's domestic temporary-non-residence rule, which can charge a gain on your return regardless of where the treaty put the taxing right while you were away. That mechanism gets its own treatment below and in a dedicated companion piece.

Relief from double taxation, and what happens when the authorities disagree

When both countries have a legitimate claim on the same income, the treaty prevents double taxation, generally by the credit method under Article 21: your residence country taxes the income but gives you a credit for the tax the other country was entitled to charge. In practice that means keeping evidence, a certificate of tax residence from the Portuguese authorities where a UK payer needs to apply a treaty rate, and clean records of what was taxed where. Relief is not automatic paperwork-free; it is claimed.

That certificate has a name worth knowing before you need it. The certificado de residência fiscal is requested through the Portal das Finanças and issued by the Autoridade Tributária, and it states that you were tax-resident in Portugal for treaty purposes in a given year. A UK payer applying a reduced treaty rate at source will generally want to see it first; without it the default domestic treatment applies and you are reclaiming afterwards, which costs time and, in a bad year, working capital. Timing is the trap: the certificate speaks to a year you must already be resident in, so the first year of a move is the awkward one. Request it early rather than in the week a payment falls due.

Where the two authorities disagree about a company's residence, the consequence is worse than slow, and this is the part most summaries get wrong. Under Article 4(3) a dual-resident company's residence is settled by the competent authorities by mutual agreement. Where they do not reach agreement, the company "shall not be entitled to any benefits provided by this Convention, except those provided by Articles 21 (elimination of double taxation), 22 (non-discrimination), and 23 (mutual agreement procedure)". Credit relief therefore survives, but the allocation rules, the reduced withholding rates and the business-profits protection do not. In other words, a company stuck in an unresolved residence dispute keeps the fallback that stops literal double taxation and loses the treaty's whole architecture for deciding who taxes what.

Nor is there a backstop that forces an answer. The Convention's arbitration Protocol is scope-limited: "The provisions of this Protocol shall apply only to issues arising under the provisions of Articles 5 (Permanent establishment), 7 (Business profits) and 9 (Associated enterprises) of the Convention", with a three-year trigger before a case can go to arbitration. An Article 4 residence dispute is not on that list. It therefore has no binding arbitration backstop and can simply end without resolution, leaving the company in the stripped-down position above indefinitely. That is the real argument for structuring to avoid dual residence rather than planning to litigate it afterwards.

The company angle, in one paragraph

If you run a UK limited company from Portugal, the treaty raises a separate exposure that this article only flags: managing the company day-to-day from Portugal can make the company itself tax-resident in Portugal or create a permanent establishment there, so "foreign" profits can quietly become locally taxed ones. The new treaty's corporate tie-breaker is a mutual-agreement procedure, not an automatic switch, and as the previous section explains, a procedure that fails leaves the company with almost no treaty at all. The Portuguese domestic residence claim is what creates the conflict in the first place. That is a full topic in its own right, covering central management and control, place of effective management, and permanent establishment, and it deserves its own read before you assume your UK Ltd is untouched: our guide to running a UK Ltd company while resident in Spain, Portugal or France takes it apart properly. It is also the strongest argument for the clean alternative below.

The clean alternative: put the income where you live, on purpose

For many relocating founders the simplest way to make the treaty a non-issue is to stop running trading profits through the UK company and instead draw employment income through a Portuguese entity, whether your own or via an employer-of-record and payroll arrangement. That puts the income tax where you actually live, deliberately, lines the salary up with IFICI's 20% flat rate if your activity qualifies, and sidesteps the residence-and-permanent-establishment questions that come from managing a UK Ltd from a Lisbon flat. Note the difference from the holding-company move above: relocating the activity and the employment to where you physically work is a change of commercial substance, not a device for reaching a treaty rate, which is why it sits on the right side of Article 27. It is not a universal answer, it does not retroactively cure a residence or permanent-establishment problem you have already created, and it needs to be set up correctly. But as a forward-looking structure it turns a tangle of treaty articles into a single, ordinary Portuguese payslip. Our Portuguese employer-of-record route walks through how that works alongside the D3 visa.

If the plan involves an exit or a few dividend-heavy years abroad

One more forward-looking note for founders planning an exit: leaving the UK does not automatically wash a future sale of your company out of UK tax, whatever Article 13(5) says about taxing rights. The UK's temporary-non-residence rule can reach back and charge a gain you realised while abroad if you were UK-resident in at least four of the seven tax years before you left and your period of non-residence is five years or less. Our companion piece on temporary non-residence and CGT for founders works through the mechanics and the counting.

Dividends sit in the same trap, and the trap has just tightened twice over. Distributions you take from your own UK close company while temporarily non-resident are charged to UK income tax in the year you come back. There used to be a carve-out for distributions paid out of trade profits arising after you left; the Autumn Budget 2025 removed it, and Finance Act 2026 amended sections 401C, 408A and 413A of ITTOIA 2005 so that every close-company distribution received during a period of temporary non-residence is chargeable on return, for individuals returning to the UK on or after 6 April 2026. The rate on that charge went up at the same time: from 6 April 2026 the ordinary dividend rate rose from 8.75% to 10.75% and the upper rate from 33.75% to 35.75%, with the additional rate unchanged at 39.35%. If the plan was "move to Lisbon, pay myself dividends from the UK company for three years, then come home", that plan now costs more than it did on both counts.

The return leg has changed too, and it is worth naming the regime properly rather than calling it "recent changes". Non-dom status and the remittance basis were abolished on 6 April 2025 and replaced by the four-year Foreign Income and Gains regime, which is open only to individuals who have been non-UK resident for the previous ten tax years, and which costs you your personal allowance and your capital gains tax annual exempt amount in any year you claim it. A founder who spends five years in Portugal and then comes back to Britain does not qualify for FIG, because five years is not ten. Price all of that in before you commit, and treat a sale or a dividend-heavy few years abroad as its own planning exercise with a UK adviser rather than a footnote to your move.

Building the immigration and tax file together, before you commit? Relovisa files the Portugal D3 and payroll routes into IFICI as one engagement, so the visa is built to carry your tax election instead of undermining it. Start with Portugal D3 + payroll →

Who should read this most closely

The founder with the highest stakes is the owner-manager who has moved full-time to Portugal, kept a UK limited company, and is drawing a mix of salary and dividends from it while working from home. That person touches almost every article in the treaty at once: residence, dividends, employment income, capital gains, and potentially corporate residence and permanent establishment. The remote employee on a UK payroll living in Portugal is a simpler case but still needs the salary and residence articles read correctly. The passive UK shareholder with a genuinely UK-run company and real UK substance has the least to worry about, but should still confirm their own residence position. In every case the treaty is the map, IFICI or the standard scale is the terrain, and a cross-border adviser is who reads them together for your specific facts.

Frequently asked questions

When did the new UK-Portugal tax treaty take effect? It was signed in London on 15 September 2025 and entered into force on 29 December 2025. The operative dates are staggered: 1 January 2026 for Portuguese taxes and withholding taxes generally, 1 April 2026 for UK Corporation Tax, and 6 April 2026 for UK Income Tax and Capital Gains Tax. The 1968 convention therefore still governed UK income tax and CGT for the whole of 2025/26, so a return you are filing now is read under the old text.

Does the treaty mean I pay 0% on my UK company dividends if I move to Portugal? No, on three counts. The 0% tier in Article 10(3) is written company-to-company: it needs a corporate beneficial owner holding directly at least 10% of the payer's capital for an uninterrupted year containing the payment date, with both companies liable to corporate tax. A founder holding shares personally sits on the 10% general cap instead. The UK charges no withholding on ordinary outbound company dividends anyway, the exception being REIT and PAIF property income distributions at 20%, rising to 22% from 6 April 2027. And what decides your bill is the Portuguese side, IFICI or the standard scale.

If I keep a UK address, can I stay UK tax-resident and avoid Portuguese tax? Not reliably. Once you live in Portugal both countries can claim you and the treaty tie-breaker decides, looking first at your permanent home, then your centre of vital interests, then where you habitually stay, then nationality. A UK address does not settle it if your actual life has moved.

How does IFICI interact with the treaty for a British founder? The treaty allocates taxing rights; IFICI decides how Portugal taxes what falls to it. Qualifying Portuguese-source employment and self-employment income is taxed at a flat 20% for 10 years, and most foreign-source income is generally exempt, counted only to set the rate on your other income. Foreign pensions are the notable exception, taxed on the 2026 progressive scale of 12.5% to 48% plus the solidarity surcharge.

What happens if I miss the 15 January IFICI registration deadline? You do not lose the regime permanently. A late inscription takes effect from the year it is filed and runs for the remainder of the ten-year period, which is anchored to your first year of Portuguese tax residence. So there is no retroactive relief and no extra year at the end: each year you file late is taxed on the standard scale and gone for good.

Does the new treaty change how selling my company is taxed? Article 13(5) gives gains on property outside paragraphs 1 to 4 exclusively to the seller's state of residence, so a Portuguese-resident founder selling a UK company that is not land-rich faces Portuguese taxing rights alone. Article 13(2) claws that back where more than half the share value comes from UK immovable property in the 365 days before the sale, and the UK's domestic temporary-non-residence rule can charge the gain on your return if you were UK-resident in at least four of the seven tax years before departure and stay away five years or less. From 6 April 2026 the same rule catches every close-company distribution, because Finance Act 2026 removed the post-departure trade profits carve-out.

Do I need a Portuguese certificate of tax residence to get treaty rates? In practice yes, whenever a UK payer has to apply a treaty rate at source. The certificado de residência fiscal is requested through the Portal das Finanças and issued by the Autoridade Tributária. Without it the payer applies its default withholding and you reclaim afterwards, so request it well before the payment date.