Here is the sentence that surprises almost every relocating client: moving to Portugal can change who inherits from you. Not because you changed your will — because you changed the law standing behind it.
Brussels IV: habitual residence takes the wheel
Under the EU Succession Regulation (the one everyone calls Brussels IV), the default law governing your entire estate is the law of your habitual residence at death — not your nationality. Become habitually resident in Portugal, and Portuguese succession law becomes the default frame, even for a lifelong New Yorker or Londoner.
Why that matters: forced heirship
Portuguese law protects close family with forced heirship: a substantial share of the estate is reserved by law for spouses, children, and in some configurations parents, regardless of what your will says. An estate plan built on common-law freedom — disinheritance clauses, unequal children's shares, large charitable dispositions — can be partially overridden by default.
The one-clause fix most people never hear about
Brussels IV contains its own escape hatch: a testator may elect the law of their nationality to govern their succession, expressly, in their will. For many common-law nationals in Portugal, that single clause preserves the plan they already built. Whether it is the right choice — and how it interacts with US estate tax, UK domicile rules, property deeds, and Portuguese stamp duty on inheritances — is a genuinely specialist question.
This is exactly where my model of one contact, specialist partners earns its keep: I flag the issue as part of every relocation, and bring in estate-planning partners for the drafting, so your move and your estate plan land as one coherent decision.
Written September 2026. Rules, thresholds, and fees change; always confirm the current position before acting. This note is general information, not legal or tax advice.