Do I file in both US and Portugal?
Usually yes, at least for the transition year. The US obligation continues regardless; the Portuguese position depends on the client's own registration rather than on the current published summary of the regime.
Which return do you prepare first?
Whichever one the credit depends on. Preparing them in the wrong order is the most common reason a credit is claimed in the wrong place, and it is also the most common reason a client ends up paying twice and reclaiming later.
Does the treaty mean I only file once?
No. A treaty allocates the tax; it does not consolidate the filing. Both obligations survive, and in some cases the treaty position itself has to be disclosed on a return before it can be relied on.
What about sub-national tax — states and provinces?
They set their own residency and sourcing rules and are not bound by the federal treaty in the same way. A position that is protected federally can still produce a state or provincial return, which is the single most common surprise in this corridor.
Can you work with my adviser in the other country?
That is how most corridor engagements run. They keep their side, we take ours and the interaction between the two, and the scope boundary is agreed in writing so nothing is duplicated or dropped.
What if I am behind in one country and current in the other?
That is the usual pattern. We map the unfiled years first and check which catch-up routes are open before anything is filed, because the route chosen for one year affects the relief available for the rest.
Does the Portuguese regime I registered under still apply to me?
That is settled from your own registration, not from whatever summary of the regime is published today. Portugal has run special regimes for new residents whose terms have changed more than once, and the version you entered under governs your position for as long as it runs. So the first document we ask for is the registration itself, with its date and the category you were accepted in. Everything else — which country taxes a pension, how relief is claimed on the US side — follows from that, and we do not guess at it.
Do I still have to file a US return living in Portugal?
Yes. The US obligation follows the person rather than the address, so it continues while you are resident in Portugal regardless of what Portugal does with the same income. That holds even in a year where the Portuguese position produces little or no tax, because the return is required on its own terms and the reporting of foreign accounts and assets runs beside it. The practical work is not deciding whether to file but deciding the order: which country has the first claim on each item of income, and what relief stops the second one taxing it again.
How do I prove which regime I was accepted under?
By producing the registration record rather than describing it. We ask for the application, the confirmation you received, the date it took effect and the category recorded against you, and we read the file against them. Clients often remember the regime by the name it had in the press at the time, which is not the same as the category on the register, and the two have drifted apart as the terms changed. Where the record cannot be found, reconstructing it is the first piece of work, because a US return prepared on a mistaken assumption about the Portuguese position has to be amended later.
Is my pension taxed in Portugal or in the United States?
It depends on the kind of pension and on the treaty article that covers it, and those articles do not all point the same way — a government pension and a private one can land in different countries. Your Portuguese registration matters as well, because the regime you entered under may treat foreign pension income differently from the ordinary resident rules. We settle the characterisation first, in writing, then prepare both returns consistently with it. Quoting a general rule here would be the wrong service: the answer is specific to your pension and your registration, and we read both before saying anything.
What does buying a flat in Portugal change for my US taxes?
Ownership alone changes little on the US return; letting it changes a good deal. Rental income is reported to the United States as well as in Portugal, in US dollars, on a consistent basis and with a consistent set of expenses across both filings. Where the property is held through a company or with other people, the structure has to be characterised before the income can be reported at all. On a later sale both countries look at the gain, and relief for the tax paid in one has to be claimed on the return of the other, which is a mapping exercise rather than a subtraction.
My accountant in Portugal says I owe nothing, so why file?
Because the two questions are separate. A Portuguese adviser is telling you about your Portuguese liability, which may well be nil under the regime you registered in. The US return is a separate obligation that exists whether or not tax is payable, and the account and asset reporting beside it is triggered by holdings rather than by income. A nil Portuguese liability can even make the US return harder, because there is then no foreign tax to set against the US charge on the same income. We prepare both sides so that neither is written on an assumption about the other.
Is the sale of foreign property taxable where I live?
For a resident, yes — worldwide gains are taxable, and the gain is computed in your own currency, so the exchange rate at purchase and at sale changes the number even when the local-currency price did not move. The country where the property sits usually taxes it too, often with a withholding or clearance step before closing, and that tax becomes a credit. A principal residence relief may apply to a home abroad on the same terms as one at home. See principal residence and foreign property.
What is a totalization agreement and how do I use one?
A social security agreement that stops you contributing to two systems for the same work, and lets periods in both count towards benefit eligibility in either. Which system you stay in depends on the agreement's rules for your situation — a seconded employee usually remains in the home system for a set period, a locally hired one usually joins the host system. You evidence it with a certificate of coverage obtained before or shortly after the assignment starts. See certificates of coverage.
