You’ve made the move to Portugal. The boxes are unpacked, the Algarve sun is doing its job — and now the UK house is sitting empty, ready to be sold. So what does HMRC want from you, what does the Autoridade Tributária want, and how do you stop being taxed in both countries?

This is one of the most common questions I get from clients in their first year as Portuguese residents. The rules aren’t quite as scary as people fear, but they are easy to get wrong if you don’t plan ahead. Here’s the 2026 guide to selling your UK home once you’ve already moved to Portugal — covering UK Capital Gains Tax, Portuguese tax on the same gain, the double taxation treaty, and the practical steps to take before you put the property on the market.

The Two Tax Systems That Now Apply to You

Once you become tax resident in Portugal — typically after spending 183 days here in a calendar year, or having your habitual home here — your worldwide gains become reportable to the Portuguese tax authority. That includes the gain on a UK property. But the UK doesn’t simply step aside. HMRC keeps its own taxing rights on UK land and property, regardless of where you live.

So when you sell the family home in Surrey from your kitchen table in Tavira, you’re potentially in the firing line of two tax authorities. The good news: the UK-Portugal Double Taxation Treaty exists precisely to stop you paying tax twice on the same gain. The less-good news: how the relief is calculated, and what you can claim, depends entirely on the order in which you handle the move and the sale.

UK Capital Gains Tax for Non-Residents

The UK has charged Capital Gains Tax (CGT) on non-residents selling UK residential property since April 2015. The rules were tightened again in 2019 and 2020 — these days, you must report the disposal and pay any CGT due within 60 days of completion using HMRC’s online “CGT on UK Property” service.

For 2026/27, the CGT rate on residential property gains for individuals is 18% within the basic rate band and 24% above it. Non-residents get the same annual exempt amount as UK residents — currently £3,000 — but no more.

The critical concession for people who have left the UK is this: as a non-resident, you don’t have to use the original purchase price as your starting point. You can choose between three methods of calculating the gain — the original cost, the value at 5 April 2015, or a time-apportioned calculation. For most expats who owned the property long before 2015, the April 2015 rebasing usually produces the smallest gain. It’s worth doing the maths on all three methods before filing.

Principal Private Residence Relief — Use It or Lose It

Principal Private Residence (PPR) relief is the rule that lets UK residents sell their main home tax-free. It can still help you as an expat, but only for the years the property genuinely was your main home — plus the final nine months of ownership, which are automatically deemed to qualify.

So if you owned the house for 20 years, lived in it for 18, and have rented it out for two before selling, roughly 18 years and nine months of the gain falls inside PPR and is exempt. The remaining sliver is taxable. This is why selling sooner rather than later, after leaving the UK, almost always produces a better tax outcome — the longer the property sits without being your main home, the smaller the proportion of the gain that’s sheltered.

One option some expats consider is making a “non-resident main residence election” to keep the property as your UK main home for CGT purposes. This is technical and only works if you spend at least 90 midnights there during the tax year. For most people who have genuinely moved abroad, this isn’t realistic — but it’s worth knowing the option exists if your move is more of a hybrid.

How Portugal Taxes the Same Gain

Now the Portuguese side. Once you’re tax resident here, Portugal taxes worldwide capital gains, including the sale of foreign property. The Portuguese rules differ from the UK in three important ways.

First, Portugal only taxes 50% of the gain on a property disposal for individuals — the other 50% is automatically exempt. This is a much more generous starting point than the UK system.

Second, that 50% is then added to your other taxable income and taxed at progressive IRS rates, which run from 14.5% up to 48% in 2026, plus the solidarity surcharge for higher earners. So the effective rate depends entirely on how much other income you have in the year of sale.

Third, Portugal allows you to deduct inflation indexation if you’ve owned the property for more than two years. The Autoridade Tributária publishes annual coefficients that uplift the original purchase price for inflation, reducing the taxable gain. For long-held properties, this can take a meaningful bite out of the calculation.

If you held NHR status under the original regime, foreign property gains were generally exempt from Portuguese tax under most treaties — including the UK one. NHR 2.0 (the IFICI regime introduced in 2024) is far narrower and does not give a general exemption on foreign capital gains, so most new arrivals can’t rely on it for this purpose.

How the Double Tax Treaty Stops You Paying Twice

The UK-Portugal Double Taxation Treaty assigns the primary taxing right on UK land to the UK. That means the UK gets to tax the gain first, and Portugal gives you a credit for the UK tax already paid.

In practice, the calculation goes like this: you work out the UK CGT, pay it within 60 days of completion, then declare the gain on your Portuguese IRS return for that year. Portugal calculates its own tax on the 50% taxable portion. You claim a foreign tax credit for the UK tax paid, up to (but not exceeding) the Portuguese tax that would otherwise be due on the same gain.

If the UK tax is higher than the Portuguese tax, the foreign tax credit wipes out the Portuguese liability entirely. If the Portuguese tax is higher — which happens occasionally when the seller has substantial other income — you’ll have a top-up to pay here. Either way, you’re not paying both authorities the full bill on the same money.

Reinvestment Relief — The Portuguese Sweetener

Portugal offers a generous reinvestment relief for residents selling a primary residence and rolling the proceeds into another primary residence inside the EU or EEA. If your UK house was your previous main home and you use the net proceeds to buy your new permanent home in Portugal (or anywhere in the EU/EEA) within 36 months — or up to 24 months before — the gain can be fully or partially exempt from Portuguese tax.

To qualify, the UK property must have been your “habitual residence” before sale and the new Portuguese property must become your habitual residence. There’s also an extended option that lets people aged 65+ (or those who are already retired) reinvest into certain pension or insurance products instead of property — useful if you’re downsizing rather than buying again.

This relief is the single biggest reason to plan the order of the sale and purchase carefully. Get it right and the Portuguese tax can vanish; get it wrong and you pay full IRS rates on the taxable portion.

Practical Steps to Take Before You Sell

The clients who get the best outcome share a pattern: they think about tax before they call the estate agent, not after. Here’s the running order I usually recommend.

1. Confirm your residency status in both countries for the tax year of sale. If you’re mid-move, the timing of the sale relative to your residency start date can shift you between two very different tax outcomes.
2. Get a 5 April 2015 valuation from a RICS-qualified surveyor if the property was owned before that date. This is the single most useful piece of paperwork you’ll need for the UK CGT calculation.
3. Gather costs of improvement — extensions, kitchens, bathrooms, conservatories. Both UK and Portuguese tax allow you to add capital improvement spending to your base cost. Receipts, invoices and bank statements are gold.
4. Check NHR status if you arrived before the original regime closed. If you’re still in the ten-year window, the treatment of foreign property gains is more favourable.
5. Plan the reinvestment if you’re buying in Portugal. Document the intention to reinvest in writing and keep the audit trail of where the proceeds go.
6. File the UK 60-day return immediately after completion. Penalties for missing this deadline start at £100 and escalate sharply.
7. Declare the gain on your Portuguese IRS the following spring, claim the foreign tax credit, and apply any reinvestment relief.

Common Mistakes I See

The biggest mistake is selling first, then getting advice. By the time you’ve completed, the planning window has closed. Once you’re a Portuguese tax resident, you can’t retrospectively change when the gain crystallised.

The second is forgetting the 60-day UK reporting deadline. The penalties hit even when no tax is due, and they compound monthly.

The third is assuming NHR shields everything. Under NHR 2.0 it generally doesn’t, and even under the old regime, the rules around UK property gains were more nuanced than the headline “exempt” status suggested.

The fourth is missing reinvestment relief by buying the new Portuguese home in only one spouse’s name when both owned the UK property — the relief works property-by-property, owner-by-owner, and a mismatch can disqualify part of the claim.

Frequently Asked Questions

Do I pay UK CGT if I sell my UK home five years after moving to Portugal?

Yes, the UK taxes non-residents on all UK residential property gains regardless of how long ago you left. However, the gain you have to declare is calculated from April 2015 (or the date you bought, if later), not from when you moved abroad. You then claim the UK tax as a credit against any Portuguese tax due on the same disposal.

Can I avoid Portuguese tax by selling before becoming resident?

Yes — if the sale completes before you trigger Portuguese tax residency, Portugal has no claim on the gain. Whether this is achievable depends on the practical timing of your move, the property market, and whether you can manage a temporary tax-residency gap. It’s a planning option worth exploring with an adviser before you list the property.

Does the 50% Portuguese exemption apply to my UK home?

Yes. Portugal taxes only 50% of capital gains on residential property disposals for individuals, regardless of whether the property is in Portugal, the UK, or anywhere else. The remaining 50% is taxed at progressive IRS rates, with foreign tax credits available.

What if my UK home was rented out for several years before sale?

Renting it out reduces the proportion of the gain covered by Principal Private Residence relief in the UK. Each year of letting (after you stopped living there as your main home) makes a slice of the gain taxable. The final nine months still automatically qualify for PPR. Portugal taxes its 50% portion the same way regardless of whether the property was rented.

Do I need to convert the gain into euros?

For the Portuguese return, yes — both the purchase cost and the sale proceeds need to be converted into euros using the exchange rates on the relevant dates. This can produce a different gain in euros than in sterling, especially if the pound has weakened over your ownership period. Always run the calculation in both currencies before deciding when to sell.

What to Do Next

Selling a UK home as a Portugal resident isn’t difficult once you know the rules, but the right answer depends heavily on your personal numbers — the original cost, the current value, the timing of your move, your other income, and whether you’re buying again in Portugal. Even a few weeks of timing can move you between two very different tax outcomes.

If you’d like to discuss how this affects your personal situation, get in touch with our team. We specialise in helping UK expats in Portugal make the most of their pensions, investments and cross-border property decisions.

Matthew Renier is a Chartered Financial Adviser at Arthur Browns Wealth Management, based in the Algarve, Portugal. He has over 20 years of experience helping British expats manage their pensions and financial planning across borders. This article is general guidance, not personal advice — please speak to a qualified adviser before acting.

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