Entry-into-force dates that actually matter.
The treaty was signed in 2025 and entered into force on 29 December 2025. From there, two effective dates split: Portugal-side withholding tax (on dividends, interest, royalties paid from PT to UK residents, or PT to UK companies) applies from 1 January 2026. UK Income Tax and Capital Gains Tax apply for tax years beginning on or after 6 April 2026. This means there is a three-month asymmetric window (1 January 2026 to 5 April 2026) where the new PT rates apply on Portugal-source flows but the old UK fiscal year still runs under the prior treaty. Treaty-based reclaims need to be filed against the date the income arose, not the date the form is submitted.
State Pension and occupational pensions.
Article 17 (Pensions) of the new DTC follows the OECD Model: pensions paid in respect of past private employment are taxable only in the State of residence. For a UK State Pension or UK occupational pension paid to a Portuguese tax resident, this means Portugal taxes; the UK does not tax. To stop UK PAYE deductions, the resident files Form DT-Individual (or DT-DTC depending on HMRC current numbering) certified by AT. Government service pensions under Article 18 remain primarily taxable in the paying State, with limited residence-State fallback for nationals of the residence State only.
Personal pension drawdowns: SIPP, SSAS.
Article 17 covers private pension income generally. UK-pension drawdowns paid to a Portuguese tax resident, including SIPP withdrawals, are taxed in Portugal under treaty allocation. Tax-free lump sums (the UK 25% PCLS / tax-free cash) are a UK domestic concept; Portugal characterises lump sums under CIRS Cat H rules and they are not automatically tax-free in Portugal. Pre-arrival pension restructuring (timing of crystallisation, partial vs full drawdown) is one of the highest-value planning levers on UK-PT moves.
Dividends, interest, royalties.
Withholding-tax rates follow Articles 10, 11, and 12 of the DTC. The exact reduced rates depend on the categorisation of the recipient (individual, qualifying corporate shareholder, parent company) and the specific share/loan/IP type. Treaty relief at source requires Portugal Form 21-RFI (or successor) certified by HMRC for UK-resident recipients of PT-source income, or HMRC certification for the reverse direction. Without prior certification, withholding occurs at the domestic rate and a refund claim is needed afterwards.
The OECD Principal Purpose Test (PPT).
Article 28 (or equivalent) 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. This is a substance test. Pre-arrival restructurings now need to pass not just domestic anti-avoidance rules but also the PPT. Document the commercial rationale.
Practical sequence for UK residents moving to Portugal.
The practical playbook hasn't changed shape, but each step now anchors to the new treaty. (1) Establish PT tax residency under CIRS art 16 (more than 183 days or habitual abode). (2) File Form DT-Individual with HMRC certified by AT to stop UK withholding on UK-source pensions and certain investment income. (3) Reflect treaty allocation in Anexo J of Modelo 3 (foreign-income annexe) with mandatory aggregation. (4) For UK State Pension, expect the UK to stop withholding (it is paid gross) and declare in Portugal as Cat H pension. (5) For pre-arrival capital-gains crystallisation, choose the date deliberately because Article 13 allocation now hinges on residence at disposal date.
Frequently Asked Questions
When did the new UK-Portugal tax treaty enter into force?
29 December 2025. Portugal applies the new treaty from 1 January 2026; the UK applies it for tax years beginning on or after 6 April 2026.
How is my UK State Pension taxed when I move to Portugal?
Under Article 17 of the 2025 DTC, the UK State Pension paid to a Portuguese tax resident is taxable only in Portugal. The UK does not withhold; HMRC pays State Pension gross. Declare in Anexo J Cat H.
What about my UK occupational pension?
Same Article 17 rule for private occupational pensions: Portugal taxes, UK does not. File Form DT-Individual to stop any UK PAYE deductions. Government-service pensions follow Article 18 (different rule).
Does the 25% UK pension tax-free lump sum stay tax-free in Portugal?
Not automatically. The UK 25% PCLS is a UK domestic concept. Portugal characterises lump sums under its own Cat H rules. Plan crystallisation timing carefully before becoming Portuguese tax resident.
How are UK dividends and interest taxed under the new treaty?
Articles 10 (dividends) and 11 (interest) of the 2025 DTC set reduced source-State withholding rates depending on recipient type. Treaty relief at source requires HMRC or AT certification. Without it, you reclaim afterwards.
Can I sell UK shares while resident in Portugal without UK tax?
Generally yes, under Article 13. Portugal taxes the gain (residence State). Two exceptions: real estate (UK situs) and shares of property-rich companies (over 50% UK real estate). Always check facts against Article 13 wording before disposal.
Does the new treaty have an anti-abuse rule?
Yes. Article 28 (or equivalent) introduces the OECD Principal Purpose Test (PPT). Treaty benefits can be denied if a principal purpose of an arrangement was to obtain them. Document commercial substance.
I moved before 6 April 2026. Which treaty applies to my UK tax?
For UK Income Tax and CGT, the prior 1968 treaty applies up to and including UK tax year 2025-26 (ending 5 April 2026). The new treaty applies from UK tax year 2026-27 onwards. Portugal-side flows already use the new treaty from 1 January 2026.