Tax residence in Portugal for U.S. citizens and green card holders

Portugal treats you as a tax resident if you spend more than 183 days there in any 12-month period beginning or ending in the year (every day with an overnight stay counts), or if you have a home there kept as your habitual residence. A Portuguese resident owes IRS on worldwide income; in the year of arrival or departure Portugal splits the year. U.S. citizens remain taxable in the United States wherever they live, and dual residence is settled by Art. 4(2) of the 1994 U.S.–Portugal Convention, read with para. 3(c) of its Protocol.

Check your status: United States and Portugal

Free, no sign-up, about 3 minutes. Conclusion under U.S. law, compared with the law of Portugal and the tax treaty.

When Portugal treats you as a tax resident

Portugal counts days over any 12-month period that begins or ends in the year concerned — not only the calendar year — and you must exceed 183 days (184 or more). A day counts if it includes an overnight stay in Portugal, even if you were there only part of the day.

With 183 days or fewer you are still resident if, on any day of that 12-month period, you had a home in Portugal in conditions suggesting a current intention to keep and occupy it as your habitual residence. A holiday or second home, or a home you plan to use only after a future return, is not enough; the courts look at where you actually live and have your family, work and economic ties.

You stayed in Portugal more than 183 days (counting every day with an overnight stay) in a 12-month period beginning or ending in this year — you are a Portuguese tax resident (art. 16(1)(a) CIRS) and owe IRS on your worldwide income. In the year you arrive you are resident from the first day of your stay (from 1 January if you were resident on any day of the previous year); in the year you leave, until your last day in Portugal, unless art. 16(14) keeps you resident for the whole year.
You had a home in Portugal in conditions suggesting a current intention to keep and occupy it as your habitual residence — you are a Portuguese tax resident (art. 16(1)(b) CIRS) even with 183 days or fewer, from the first day of your stay. The conclusion depends on the facts: owning or renting a home is not enough without a current intention to live there.
You perform public functions or a public mission abroad in the service of the Portuguese State — you are a Portuguese tax resident (art. 16(1)(d) CIRS) regardless of the days spent in Portugal.
On 31 December you were a crew member of a ship or aircraft serving an entity resident, or with its seat or effective management, in Portugal — you are a Portuguese tax resident for that year (art. 16(1)(c) CIRS).

When you are a nonresident

183 days or fewer in every 12-month period, no home in Portugal kept as habitual residence, and no Portuguese public service or crew position — you are not a Portuguese tax resident. Portugal taxes only your Portuguese-source income, for example pay for work done in Portugal (25% final withholding) or rent from Portuguese property.
You did not exceed 183 days, but it is unclear whether your home in Portugal shows an intention to keep it as your habitual residence. The tax authority and courts decide this on the facts (where you actually live, your family, work and assets); if they find such an intention you are resident. Keep evidence of where you live, and update your address with the tax authority when you leave.

Where the rules of Portugal clash with U.S. tax rules

Collision: more than 183 days in Portugal while the U.S. also treats you as resident or citizen. Portugal treats you as resident because you spent more than 183 days there in a 12-month period; the United States taxes you on worldwide income as a citizen, green-card holder or substantial-presence resident. Art. 4(2) of the 1994 Convention decides treaty residence (permanent home → centre of vital interests → habitual abode → nationality → mutual agreement) — for a U.S. citizen or green-card holder read with Protocol para. 3(c): without a substantial presence in the U.S., Portugal accepts you as a U.S. resident only if the first two tie-breaker steps point to the U.S. Even if the treaty gives residence to Portugal, the U.S. keeps taxing its citizens (saving clause, Protocol para. 1(b)); double tax is relieved under Art. 25.
Collision: a home kept in Portugal can make you resident without 183 days. Portugal treats you as resident if you have a Portuguese home in conditions suggesting a current intention to keep it as your habitual residence, even after a short stay. Under the treaty such a home will usually also be a «permanent home available to you»: if your only permanent home is in Portugal, Art. 4(2)(a) points to Portugal; with homes in both countries, the centre of vital interests decides. A U.S. citizen remains taxable in the U.S. either way (Protocol para. 1(b)).
Collision: U.S. citizens stay taxable in the United States even as Portuguese residents. Portugal taxes you on worldwide income as a resident; the United States taxes its citizens wherever they live. The saving clause (Protocol para. 1(b)) lets the U.S. tax you as if the treaty did not exist, but keeps Art. 25 (relief) and the pension rules of Art. 20(1)(b) and (4). Relief works in steps: Portugal credits U.S. tax only on income the U.S. may tax other than by citizenship (e.g. U.S.-source dividends, U.S. real estate, work done in the U.S.) — Art. 25(3)(a), art. 81 CIRS; income the U.S. taxes only because of citizenship is treated as Portuguese-source to the extent necessary, so the U.S. credits the Portuguese tax on it (Art. 25(1)–(2)).

What else to know

Portugal counts 183 days over any 12 months, and a day means a night. The Portuguese threshold is more than 183 days in any 12-month period beginning or ending in the tax year — a stay from July to June can make you resident in both calendar years — and every day that includes an overnight stay in Portugal counts. The U.S. substantial-presence test counts calendar-year days with a weighted look-back, so the two counts rarely match.
Treaty residence test for U.S. citizens and green-card holders. Portugal regards a U.S. citizen or green-card holder as a U.S. resident for the Convention only if he or she has a substantial presence in the United States, or the permanent-home / centre-of-vital-interests / habitual-abode steps of Art. 4(2)(a)–(b) point to the U.S. and not to a third country (Protocol para. 3(c)). If you live in Portugal without such a link to the United States, Portugal treats you as resident only in Portugal.
Year of moving: Portugal splits the year, the U.S. does not for citizens. In the year you arrive Portugal treats you as resident from the first day of your stay; in the year you leave, until your last day of presence (art. 16(3)–(4) CIRS), and you file a separate Portuguese return for each period. Two exceptions: if you spent more than 183 days in Portugal in the year of departure and your later income that year is taxed abroad at less than 60% of the Portuguese tax (outside the EU/EEA — this includes the U.S.), you stay resident for the whole year (art. 16(14)–(15)); and if you come back the following year, you are treated as resident for the whole year (art. 16(16)). U.S. citizens are taxed for the whole year in the U.S. regardless.
Working in Portugal while not Portuguese-resident. Pay for work physically performed in Portugal is Portuguese-source income, taxed at a 25% final rate for non-residents. If you are a U.S. resident under the Convention, Portugal may not tax it if all conditions of Art. 16(2) are met: no more than 183 days in Portugal in any 12-month period commencing or ending in the taxable year, an employer not resident in Portugal, and pay not borne by a Portuguese permanent establishment or fixed base. Self-employed: Art. 15(1) — fixed base or 183 days.
IFICI («NHR 2.0»): 20% for qualifying newcomers. If you were not resident in Portugal in any of the previous five years and work in a qualifying activity (research and higher education, qualified jobs in companies with investment-incentive contracts, highly qualified professions in qualifying or exporting companies, R&D staff, certified start-ups, etc.), you may pay 20% on net employment and self-employment income from that activity for 10 years; most foreign income is exempt with progression (art. 81(4) CIRS). Register by 15 January of the year after you became resident — later registration works only from that year. For a U.S. citizen the regime lowers only Portuguese tax: the U.S. still taxes worldwide income, and lower or exempt Portuguese tax means a smaller U.S. foreign tax credit.
Non-habitual resident (NHR) regime: closed to new entrants. The NHR regime was repealed from 2024. It still applies for the rest of the 10-year period to people already registered and, under transitional rules, to those who became resident by the end of 2024 with qualifying pre-2024 documents. Registration matters: the Supreme Administrative Court has ruled that the NHR registration request is a condition of access to the regime, and that a late request works only from the year of registration.
Former Portuguese residents returning from the U.S. (art. 12-A CIRS). If you were a Portuguese resident at some point, were not resident in the previous five years and become resident again by 2026, 50% of your employment and business income is excluded from IRS for 5 years (capped by reference to EUR 250,000 for people who became resident from 2024). «Resident» here means resident under art. 16 CIRS: a stay in Portugal for part of one of those years without meeting any art. 16 criterion does not rule out the regime (STA, uniformisation of case law, April 29, 2026). Taxpayers up to 35 may instead use IRS Jovem (art. 12-B), which cannot be combined with art. 12-A, NHR or IFICI.
Pensions, Social Security and government service. Private pensions for past employment and annuities are taxable only in the country where you live (Art. 20(1)(a) and (2)). Social security benefits and other public pensions paid by one country may also be taxed by that country (Art. 20(1)(b)) — so U.S. Social Security paid to you in Portugal, or a Portuguese state pension paid to you in the U.S., can be taxed at source; Art. 20(1)(b) is an exception to the saving clause, so it applies to U.S. citizens too. Pay and pensions for government service are generally taxed only by the paying country, with an exception for residents who are nationals of the other country (Art. 21). Where both countries tax, the country of residence gives the credit (Art. 25).
Leaving Portugal: no general exit tax, except on crypto-assets. Portugal's IRS code has no general exit tax on shares or other assets of individuals who move abroad; the exception is crypto-assets that are not securities, where losing residence is treated as a disposal (art. 10(1)(k) and (25) CIRS; crypto held 365 days or more is excluded). Report the change of residence within 60 days and appoint a representative or join electronic notifications (art. 19 LGT). U.S. rules on giving up citizenship or a green card are separate and are covered in the U.S. section.
Certificates of residence and registration. To claim treaty benefits in the U.S. as a Portuguese resident, request a tax residence certificate on the Portal das Finanças (issued online at once). To claim them in Portugal as a U.S. resident, use IRS Form 6166. You need a Portuguese tax number (NIF) to deal with the tax authority; keep your address up to date — a change is ineffective until reported, and a change of residence status must be reported within 60 days.
Social security: Portugal–U.S. agreement. Portugal and the United States have a social security agreement; employees sent to Portugal by a U.S. employer can stay in U.S. social security for up to 60 months (plus 12) with certificate USA/PT 1, and vice versa. Otherwise Portuguese contributions apply: 11% employee and 23.75% employer; self-employed 21.4% on 70% of service income. Social security contributions are outside the income tax treaty (Protocol para. 2(a)).
Which treaty applies: the 1994 Convention. The U.S.–Portugal income tax Convention with Protocol was signed in Washington on 6 September 1994 and approved in Portugal by Resolução da Assembleia da República n.º 39/95; the Portuguese tax authority lists it as in force since 1996. Residence tie-breaker: Art. 4(2) with Protocol para. 3(c); saving clause: Protocol para. 1(b); employment: Art. 16 (183 days in any 12-month period); independent services: Art. 15; pensions: Art. 20; relief: Art. 25.

How dual residence is resolved

If both countries treat you as a resident, Art. 4(2) of the treaty applies: Convention between the Government of the Portuguese Republic and the Government of the United States of America for the avoidance of double taxation and the prevention of fiscal evasion with respect to taxes on income, with Protocol, signed at Washington on 6 September 1994 (Portugal: Resolução da Assembleia da República n.º 39/95 of 12 October 1995; Aviso n.º 35/96, DR 09.01.1996). The tests are applied in order — permanent home, center of vital interests, habitual abode, nationality, and finally mutual agreement between the tax authorities. U.S. citizens remain taxable in the United States under the saving clause.

The treaty in detail: income, rates, the 183-day rule →

Terms you will come across in Portugal

residência fiscal: tax residence
residência habitual: habitual residence — a home kept with a current intention to live in it makes you resident even with fewer than 184 days (art. 16(1)(b) CIRS)
IRS / CIRS: Portuguese personal income tax / the Personal Income Tax Code
IFICI («NHR 2.0»): 20% rate on qualifying employment and self-employment income of newcomers for 10 years
NIF: Portuguese tax number needed for dealings with the tax authority
Portal das Finanças: online portal of the Portuguese tax authority, where a tax residence certificate is issued

Questions

I am a U.S. citizen — do I still pay U.S. tax if I live in Portugal?

Yes. The United States taxes its citizens wherever they live, and the saving clause (Protocol para. 1(b)) keeps that right even if the treaty makes you a Portuguese resident. Portugal credits U.S. tax only on income the U.S. may tax other than by citizenship (Art. 25(3)(a), art. 81 CIRS); income the U.S. taxes only because of citizenship is treated as Portuguese-source to the extent necessary, so the U.S. credits the Portuguese tax on it (Art. 25(1)–(2)).

Which treaty applies between the U.S. and Portugal?

The income tax Convention with Protocol signed in Washington on 6 September 1994; the Portuguese tax authority lists it as in force since 1996. The tie-breaker is in Art. 4(2) with Protocol para. 3(c): without a substantial presence in the U.S., Portugal accepts a U.S. citizen or green card holder as a U.S. resident only if the permanent-home, centre-of-vital-interests or habitual-abode steps point to the U.S.

Can a U.S. citizen use Portugal's IFICI regime?

If you were not resident in Portugal in any of the previous five years and work in a qualifying activity, you may pay 20% on net employment and self-employment income from that activity for 10 years; register by 15 January of the year after you became resident. The regime lowers only Portuguese tax: the U.S. still taxes worldwide income, and a lower Portuguese tax means a smaller U.S. foreign tax credit. The older NHR regime is closed to new entrants since 2024.

Sources

Legislation and official guidance

art. 16(1)–(2) Código do IRS (CIRS) — You are a Portuguese resident for a year if in that year you (a) stayed in Portugal more than 183 days, consecutive or not, in any 12-month period beginning or ending in that year; (b) having stayed less, had in Portugal on any day of that period a dwelling in conditions suggesting a current intention to keep and occupy it as your habitual residence; (c) were on 31 December a crew member of a ship or aircraft serving an entity resident, or with its seat or effective management, in Portugal; or (d) performed public functions or missions abroad in the service of the Portuguese State (including as a Member of the European Parliament, art. 16(13)). A day of presence is any day, whole or partial, that includes an overnight stay in Portugal.
art. 16(3)–(5) CIRS (partial-year residence) — If you meet criterion (a) or (b), you are resident from the first day of your stay in Portugal — unless you were resident on any day of the previous year, in which case from 1 January. Residence ends on the last day of presence in Portugal, subject to art. 16(14) and (16). Residence is assessed separately for each member of a household.
art. 16(14)–(16) CIRS (year of departure) — You stay resident for the whole year of departure if you spent more than 183 days in Portugal that year and, after leaving, earn income that would have been taxable and not exempt had you remained resident — unless you show that the income is taxed, because of your residence, by a similar income tax in another EU/EEA State or, elsewhere, at a rate of at least 60% of the Portuguese rate. You are also resident for the whole year if you become resident again in the year after the one in which you lost residence.
art. 15 CIRS — Residents are taxed on all their income, including income obtained abroad; non-residents only on income obtained in Portugal. In a year of partial residence each status applies to its own period.
art. 18(1)(a), (h), (l) CIRS — Portuguese-source income includes employment income from work performed in Portugal or paid by an entity resident or with a permanent establishment in Portugal, income from and gains on Portuguese real estate, and pensions paid by Portuguese entities.
art. 71(1), (4), (17) CIRS — Final withholding: 25% on employment income, business and professional income and pensions obtained in Portugal by non-residents; 28% on most capital income paid by Portuguese entities; 35% where income is paid to accounts for unidentified third parties or involves listed low-tax jurisdictions.
art. 19(1), (3)–(8), (15) Lei Geral Tributária (LGT) — Your tax domicile is the place of your habitual residence; it must be communicated to the tax authority and a change is ineffective until communicated. A change of residence status must be reported within 60 days. Residents abroad (and residents absent for more than six months) must appoint a tax representative resident in Portugal — optional for EU/EEA cases, and not required if you join the electronic notification service (Morada Única Digital / Portal das Finanças notifications).
Art. 4(1)–(2) U.S.–Portugal Convention (Washington, 6 Sep 1994) — Resident = a person liable to tax in a State by reason of domicile, residence, place of management, place of incorporation or a similar criterion, but not a person liable there only on income from sources there. Dual-resident individual: (a) permanent home; if a home in both States, the State of closer personal and economic relations (centre of vital interests); (b) if the centre of vital interests cannot be determined, or there is no permanent home in either State — habitual abode; (c) nationality; (d) mutual agreement.
Protocol to the U.S.–Portugal Convention, para. 3(c) (on Art. 4(1)) — Portugal treats a U.S. citizen or green-card holder as a U.S. resident only if he or she has a substantial presence in the United States, or would be a resident of the United States, and not of a third country, under Art. 4(2)(a) and (b).
Protocol to the U.S.–Portugal Convention, para. 1(b)–(c) (saving clause) — Each State may tax its residents (as determined under Art. 4), and the United States its citizens (including a former citizen whose loss of citizenship had tax avoidance as a principal purpose, for 10 years), as if the Convention had not come into effect. Exceptions: Arts. 9(2), 20(1)(b) and (4), 25 (relief), 26 (non-discrimination), 27 (mutual agreement); and Arts. 21, 22, 23 and 29 for individuals who are neither citizens nor immigrants of that State.
Art. 25 U.S.–Portugal Convention (relief from double taxation) — (1) The United States credits Portuguese income tax to its citizens and residents. (2) For a U.S. citizen resident in Portugal, income the United States may tax solely by reason of citizenship is deemed to arise in Portugal to the extent necessary to avoid double taxation, provided the U.S. tax is not less than it would be for a non-citizen. (3)(a) Portugal deducts U.S. income tax on income the United States may tax under the Convention (other than solely by reason of citizenship), up to the Portuguese tax attributable to that income; (3)(c) treaty-exempt income may be taken into account for the rate.
art. 81(1)–(2), (4) CIRS — Foreign tax credit limited to the lower of the foreign income tax paid and the Portuguese tax on that income; under a tax treaty, not more than the tax the treaty allows the source State to levy. IFICI beneficiaries: foreign employment, business, capital, rental and capital-gains income is exempt but counts for the rate.
arts. 57(1), (6) and 60(1) CIRS; art. 143 CIRS — IRS is assessed on the calendar year (art. 143). The annual return (Modelo 3) for the previous year's income is filed electronically from 1 April to 30 June (art. 60(1)); if you had two residence statuses in the same year you file one return for each (art. 57(6)).
Art. 16(1)–(2) U.S.–Portugal Convention (dependent personal services) — Salary for work exercised in the other State may be taxed there, unless the employee is present there not more than 183 days in any 12-month period commencing or ending in the taxable year concerned, the employer is not a resident of that State, and the pay is not borne by a permanent establishment or fixed base of the employer there.
Art. 15(1) U.S.–Portugal Convention (independent personal services) — Professional income is taxable only in the State of residence unless the person has a fixed base regularly available in the other State (income attributable to it) or stays there 183 days or more in any 12-month period commencing or ending in the taxable year (income from activities performed there).
art. 58-A Estatuto dos Benefícios Fiscais (IFICI), added by Lei n.º 82/2023 — New residents who were not resident in Portugal in any of the previous five years and work in listed qualifying activities (higher education and research, qualified jobs in companies with contractual investment benefits, highly qualified professions in qualifying or exporting companies, R&D staff, certified start-ups, and others) may be taxed at 20% on net category A and B income from those activities for 10 consecutive years from the year of registration as resident. Not available to former NHR beneficiaries or ex-resident regime users; usable only once.
Portaria n.º 352/2024/1 of 23 Dec 2024, art. 2(1) — The IFICI registration request must be filed by 15 January of the year after the one in which you became resident; a late request takes effect from the year of registration for the remainder of the period (art. 58-A(7) EBF).
art. 236(3)–(5) Lei n.º 82/2023 (State Budget 2024) — transitional NHR rules, reproduced under art. 16 CIRS — The NHR regime (former art. 16(8)–(12) CIRS) was repealed from 2024. It continues to apply for the remainder of the 10-year period to those already registered, to those who met the residence conditions by 31 Dec 2023, and to those who became resident by 31 Dec 2024 holding one of the listed pre-2024 documents (work contract, lease, school enrolment, residence visa, etc.) and who applied for NHR registration; a late registration takes effect only from the year in which it is made.
art. 12-A CIRS (regime for former residents) — 50% of employment and business income is excluded from tax for 5 years, within a cap set by the upper limit of the first bracket of art. 68-A CIRS (EUR 250,000; the cap applies to people who became resident from 2024), for people who become resident under art. 16(1)–(2) by 2026, were not resident in any of the previous five years but were resident at some earlier time, and have their tax affairs in order. Not combinable with NHR.
art. 12-B CIRS (IRS Jovem) — Taxpayers up to 35 who are not dependants may elect a partial exemption of category A and B income for 10 years of earning income: 100% in year 1, 75% in years 2–4, 50% in years 5–7, 25% in years 8–10, capped at 55 × IAS. Not available to NHR or IFICI beneficiaries or users of art. 12-A.
Art. 20 U.S.–Portugal Convention (pensions, social security, annuities, alimony) — (1)(a) Pensions and similar remuneration for past employment are taxable only in the State of residence; (1)(b) social security benefits and other public pensions paid by a Contracting State may be taxed in that State; (2) annuities are taxable only in the State of residence; (3) alimony is taxable only in the recipient's State of residence; (4) child support is taxable only in the payer's State of residence.
Art. 21 U.S.–Portugal Convention (government service) — (1) Pay, other than a pension, from a Contracting State or its subdivision or local authority for services rendered to it is taxable only in that State, but only in the other State if the services are rendered there by a resident of that other State who is its national or did not become resident there solely to render the services; (2) a government-service pension is taxable only in the paying State, but only in the other State if the individual is a resident and national of that other State; (3) pay and pensions for services in connection with a government business fall under Arts. 15, 16, 18, 19 and 20.
art. 10(1)(k) and (25) CIRS — For crypto-assets that are not securities, losing Portuguese residence is treated as a disposal for consideration (deemed sale on exit). Crypto-assets held for 365 days or more are excluded from the gains rules (art. 10(22)). No comparable exit charge on shares or other assets of individuals appears in art. 10.
Autoridade Tributária e Aduaneira (DSRI), note of 14 Dec 2021 on certification of tax residence — Since 1 Jan 2022 a Portuguese tax residence certificate for treaty purposes is requested online on the Portal das Finanças («Pedir Certidão» → «Residência Fiscal») and issued immediately; the AT says it is the only document attesting Portuguese residence for treaty benefits, and it is attached to the foreign form instead of having the form stamped.
IRS — Form 6166, Certification of U.S. tax residency
Instituto da Segurança Social — Guia Prático «Destacamento de trabalhadores de outros países para Portugal» (published 15 Nov 2021) — Under the Portugal–United States social security convention, employees posted to Portugal can stay covered in the sending country for up to 60 months (extendable by 12 months), on form USA/PT 1 (USA/PT 1 A for performing artists on short tours).
gov.pt — Social Security contributions paid by employers — Employees in the general scheme: employer 23.75%, employee 11%, total 34.75%.
Instituto da Segurança Social — Guia Prático «Trabalhador Independente» (published 16 May 2025) — Self-employed workers: 21.4% (25.2% for sole traders/ENI) on relevant income, which is 70% of income from services (20% of income from sales of goods).
U.S.–Portugal Convention and Protocol, signed at Washington on 6 Sep 1994; approved by Resolução da Assembleia da República n.º 39/95 (Diário da República I-A, n.º 236, 12 Oct 1995); Art. 30 — The Convention enters into force on the exchange of instruments of ratification and has effect for withholding taxes on amounts paid from 1 January next following, and for other taxes for taxable years beginning on or after 1 January next following.
Autoridade Tributária e Aduaneira — practical table of Portugal's tax treaties; Guia fiscal Comunidades Portuguesas — EUA (July 2026) — The AT lists the U.S. Convention under Resolução AR n.º 39/95 and Aviso n.º 35/96 (published 9 Jan 1996) as «in force since 01-01-1996»; withholding limits: dividends 5%/10%/15% (Art. 10), interest 10% (Art. 11), royalties 10% (Art. 13).
art. 68 CIRS (general rates) — Progressive IRS scale; the current text was last amended by Decreto-Lei n.º 212/2026 of 4 Nov 2026 (rates from 12.2% to 48%); a solidarity surcharge of 2.5% (EUR 80,000–250,000) and 5% (above EUR 250,000) applies on top (art. 68-A).
art. 72(1)(b)–(c), (2), (6) CIRS — Special flat rates: 28% on other income of non-residents not subject to withholding and on net gains on securities; 25% on residential rental income; 25% on income of non-residents attributable to a Portuguese permanent establishment and on their employment income and pensions not subject to withholding. Residents may opt to aggregate most of these items with their other income.
Art. 4(2)(a) of the Portugal–United States Convention — A dual-resident individual is deemed to be a resident only of the State in which he has a permanent home available to him; if he has a permanent home available in both States, of the State with which his personal and economic relations are closer (centre of vital interests).
Protocol to the Portugal–United States Convention, para. 3(c) (with reference to Art. 4(1)) — Portugal shall treat a United States citizen or an alien admitted to the United States for permanent residence (green-card holder) as a resident of the United States only if he has a substantial presence in the United States, or would be a resident of the United States and not of a third country under the principles of Art. 4(2)(a) and (b).
Art. 4(2)(b) of the Portugal–United States Convention — If the State of the centre of vital interests cannot be determined, or if he has no permanent home available in either State, he is deemed to be a resident only of the State in which he has an habitual abode.
Art. 4(2)(c), (d) of the Portugal–United States Convention — If he has an habitual abode in both States or in neither, he is deemed to be a resident only of the State of which he is a national (c); if he is a national of both States or of neither, the competent authorities settle the question by mutual agreement (d).

Case law

Tribunal Central Administrativo Norte (TCAN), Tax Litigation Section, 01219/21.6BEPRT, 2025-01-30 — Tax domicile (art. 19 LGT) and tax residence for IRS are different concepts. A taxpayer who by mistake filed her 2019 return as a Portuguese resident could rebut her own return: Brazilian tax documents showed that she and her husband lived in Brazil, so the 183-day and dwelling criteria were not met and the assessment of her Brazilian income was annulled.
Tribunal Central Administrativo Sul (TCAS), Tax Litigation Section, 443/20.3BELRA, 2025-11-27 — Art. 16(1)(b) CIRS requires, besides a dwelling, a current intention to keep it as habitual residence — the place where a person normally lives and has the centre of family, social, professional and economic interests. A taxpayer who kept the same flat in Portugal and returned to it after each short absence abroad was resident; a foreign residence certificate issued later proved nothing about the earlier years, and the burden of proving non-residence was on the taxpayer.
Centro de Arbitragem Administrativa (CAAD), tax arbitration, 226/2023-T, 2024-01-02 — A football coach whose contract in China began on August 1, 2016, after 213 days in Portugal (no earlier departure was proven), stayed resident for all of 2016 under art. 16(14)–(15) CIRS because the Chinese tax on his later income was below 60% of the Portuguese tax. For 2017, owning a home in Portugal where his family lived did not make him resident without a current intention to occupy it as habitual residence (residence is assessed per person, art. 16(5)); the 2017 assessment was annulled.
Supremo Tribunal Administrativo (STA), Plenary of the Tax Litigation Section, 084/25.9BALSB (uniformisation of case law), 2026-01-28 — Filing the request for registration as a non-habitual resident under art. 16(10) CIRS (wording in force in 2023) is a condition of access to the NHR regime; meeting the substantive conditions is not enough without the request.
Supremo Tribunal Administrativo (STA), Tax Litigation Section, 0842/23.9BESNT, 2024-05-29 — NHR registration is declaratory, not a grant by the tax authority: if the conditions of art. 16(8) are met (assessed for the year of becoming resident), a request filed after the 31 March deadline is still possible, but the regime then applies only from the year of the NHR registration onwards.
Supremo Tribunal Administrativo (STA), Plenary of the Tax Litigation Section, 0214/25.0BALSB (uniformisation of case law), 2026-04-29 — For the former-resident regime (art. 12-A CIRS; here in the wording then in force, «three previous years» — now five), the condition of not having been resident refers to tax residence as defined in art. 16 CIRS. The tax authority may refuse the regime only if it shows that one of the art. 16 criteria was met in one of those years; it is not enough that the taxpayer stayed in Portugal for part of that year, for less than 183 days. The arbitral decision that had refused the regime was annulled.

Updated 2026-11-10. The result is for information only and is not tax or legal advice. Tax authorities and courts may interpret the rules differently, including because of circumstances not covered here, and the law changes. Consult a qualified adviser before making decisions.

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