Change of Tax Residence During the Year: How Income Is Allocated in the IRS Return
António Pratas Nunes | Lawyer
Relocating to Portugal involves far more than visas and housing, it also raises important tax questions that can affect your global income from the moment residency begins. In a year of arrival or departure, Portuguese tax rules may divide the year into separate residency periods with different obligations. This insight explores how partial tax residence works and why timing matters when planning a move to Portugal.
When Do You Become a Tax Resident in Portugal? Income and IRS Implications Explained
When we think about moving to another country and making Portugal our new home, the questions seem endless:
- Which visa do I need to live here legally?
- Which school should I enrol my children in?
- Should I buy or rent?
- Are there any tax benefits I should know about?
- What happens to my car and driving licence?
- Can I bring my
belongings from abroad to my new house?
Amid all the logistical challenges that come with an international move, there is one question that often gets pushed to the back of the list, yet it is arguably the most important of all, as it directly determines the financial resources available to address everything else:
from what moment am I considered a tax resident in Portugal, and what are my tax obligations from that date?
In this insight, we explore the concept of partial tax residence, when a person becomes a tax resident in Portugal, and what that means for their tax obligations and liabilities.
When do you become a tax resident in Portugal?
Under Portuguese tax law, specifically Article 16 of the Personal Income Tax Code (CIRS), a person is considered a tax resident in Portugal if, in a given year, they spend more than 183 days in Portuguese territory, whether consecutive or not.
However, even without meeting this threshold, a person may still be considered a tax resident if they have a property available to them in Portugal under conditions that suggest an intention to maintain and occupy it as their habitual residence.
In practical terms, this means that as soon as you move to Portugal and establish a home, whether through a purchase or a rental, that property may be treated as your habitual residence and trigger tax residency.
It is worth noting that the Portuguese Tax Authority already has access to information about properties registered in Portugal, as well as rental agreements, which are legally required to be registered. That said, establishing tax residency is not automatic: it requires a formal act of communication.
The taxpayer must notify the Tax Authority of their new address, so that it is recognised as their habitual residence and tax residency is formally established. Importantly, once residency is confirmed, it is deemed to have applied from the first day of presence in Portuguese territory in that year - not from the date of notification. The timing of your arrival therefore matters as much as the formalities that follow.
It is also important to highlight that those who meet the conditions for tax residency, whether through the 183-day rule or through the availability of a habitual residence, are considered residents from the first day of their period of presence in Portugal. The only exception applies when the individual was already a resident in Portugal at any point in the prior year, in which case they are deemed to have been resident since the first day of that year.
One further point worth noting for couples and families: it may seem logical to assume that if one member of a household is resident in Portugal, the others are too. This is not the case. Tax residency is assessed individually for each taxpayer, regardless of family ties or shared living arrangements.
What happens when you leave Portugal during the year?
The rules work symmetrically in both directions. The loss of tax residency occurs from the last day of presence in Portuguese territory. This means that the year of departure is also a year of partial residence, with distinct obligations for each period.
What are your tax obligations once you become a resident?
This is where the real implications begin to materialise. Portuguese tax residents are subject to IRS on their worldwide income. From the moment you become a tax resident in Portugal, all income earned anywhere in the world must be declared here.
To put this into concrete terms:
if you become a tax resident on 30 August 2026, you will be required to declare all income earned worldwide from that date through to 31 December 2026. And this is not merely a declaratory exercise - that income will, in principle, be subject to taxation in Portugal.
This naturally raises a concern that we hear frequently: if I am already paying tax on this income abroad, is it fair to pay again in Portugal?
This is a legitimate question. Portugal has an extensive network of double taxation treaties which, depending on the nature of your income and the country of source, will determine which state has the primary right to tax and which mechanism applies to avoid double taxation.
Under most treaties, relief is granted either through the exemption method (the income is excluded from Portuguese taxation) or the credit method (Portuguese tax is reduced by the amount paid abroad). The specific outcome depends on your treaty, your income type, and your individual circumstances - which is precisely why tailored advice matters.
What is clear is that the
existence of foreign taxation does not eliminate the obligation to declare the income in Portugal.
What should you take away from this?
Three principles are worth retaining from this insight.
- Tax residency is determined either by the time spent in Portuguese territory or by the availability of a habitual residence as at 31 December;
- From the moment you become a resident, you are required to declare all worldwide income and that income will generally be subject to Portuguese taxation, subject to applicable treaties or exemptions;
- The date you become a tax resident is not a technicality. It determines how much of your worldwide income falls within the Portuguese tax net in your first year and whether you can access regimes such as IFICI that significantly reduce that burden.
This is precisely why planning ahead matters. Determining the exact date on which you become a tax resident, understanding the rates applicable to your income streams, assessing your eligibility for the IFICI regime, and structuring your affairs accordingly - ideally before you arrive - can make a material difference to your overall tax position.
Conclusion
The right time to act is before you arrive, not after. Defining your residency date, assessing your eligibility for the IFICI regime, and understanding how your income will be treated in Portugal are decisions that should be made in advance and they are decisions where the detail matters. If you would like to discuss your specific situation, we invite you to reach us through our contact form.
We will carefully assess your situation and advise on the most effective course of action to help ensure that your case receives the decision it is legally entitled to.
