UK-⁠Portugal double tax treaty guide

Short answer: the treaty allocates taxing rights, but the return still needs a reporting position

The UK-Portugal convention does not make filing obligations disappear. It decides which country has taxing rights, whether source-state withholding is capped, and how Portugal should treat the same income on the Modelo 3. For a UK-to-Portugal move, map each income stream before filing:

• UK State Pension and private pensions
• SIPP, SSAS, and lump-sum withdrawals
• Dividends, interest, and royalties
• Capital gains on property-rich entities
• Principal Purpose Test (PPT) risk and evidence of the main purpose

Entry into force

The convention entered into force on 29 December 2025. It applies to withholding taxes in both countries from 1 January 2026. Other covered Portuguese taxes use it for periods beginning on or after that date; UK Corporation Tax uses financial years beginning on or after 1 April 2026, and UK Income Tax and CGT use tax years beginning on or after 6 April 2026.

State Pension, private pensions and government service

The treaty’s ordinary pension rule gives the residence state the right to tax pensions, except government-service pensions covered by their separate treaty rule. For UK State Pension and qualifying private pensions received by a Portuguese treaty resident, Portugal has the exclusive taxing right. State Pension is paid without withholding; a UK liability outside applicable treaty relief may be collected through another PAYE code or a return.

Under the government-service treaty rule, government-service remuneration and pensions are normally taxable only in the paying state. If the recipient is not a national of that state but is a national of the other state, both states may tax, with relief under the treaty’s double-taxation rules. This exception does not automatically exempt the pension in the paying state.

Personal pension drawdowns: SIPP, SSAS

UK-pension drawdowns paid to a Portuguese tax resident, including SIPP withdrawals, are taxed in Portugal under treaty allocation. The UK pension commencement lump-sum label does not create a Portuguese exemption. Portuguese treatment depends on the scheme, contributions, basis, payment form, and the Category H rules applicable to the facts. Pre-arrival pension restructuring (timing of crystallisation, partial vs full drawdown) is one of the most consequential decisions on a UK-PT move.

Dividends, interest, royalties

The treaty’s dividend, interest and royalty rules limit source-country tax on dividends, interest and royalties when treaty requirements are met. The rates depend on the payment and recipient.

For Portuguese-source payments to a UK resident, the Portuguese relief-at-source claim uses Form 21-RFI and UK residence evidence issued by HMRC as required by AT. In the reverse direction, a Portuguese resident uses the applicable UK relief procedure, including DT-Individual where appropriate, with a separate Portuguese Certificate of Residence attached. AT does not certify the DT-Individual form itself. HMRC processes the claim; the payer changes PAYE only after the applicable authorisation.

Capital gains: shares, real estate, property-⁠rich entities

The treaty’s capital-gains rule allows the country where real estate is located to tax the related gain. It also covers shares and comparable interests that derived more than 50% of their value, directly or indirectly, from real estate in that country at any time during the 365 days before disposal. Assets belonging to a permanent establishment have a separate rule.

Gains outside the treaty’s specific capital-gains categories are allocated to the seller’s residence state. The stock exchange on which a share is listed does not decide the result.

The OECD principal purpose test (PPT)

The treaty’s anti-abuse rule introduces the OECD BEPS Action 6 Principal Purpose Test. Treaty benefits can be denied if obtaining them was one of the principal purposes of an arrangement, unless granting the benefit accords with the treaty's object and purpose. Pre-arrival restructurings must now pass not just domestic anti-avoidance rules but also the PPT. Document the commercial rationale.