International mobility of families: protecting children, assets and residence

Moving an entire family to another country is not simply the sum of individual immigration processes: each member — spouses, children, dependents — may be subject to different connecting factors depending on age, nationality and ties to each territory, and this must be mapped before the move, not after.

Family law, succession law and tax law each treat every person as an individual subject of rights. A couple may hold different nationalities, the children may have been born in a third country, and assets may be registered in the name of only one spouse. Each of these elements is assessed under different connecting factors — nationality, domicile, habitual residence, location of assets — which do not always point to the same country.

Custody matters, authorization for minors to travel, and the exercise of parental authority are governed by each jurisdiction's own rules, and a change in the child's habitual residence can alter which country has jurisdiction to decide on these issues. This is particularly sensitive for families already divorced or undergoing separation.

The property regime adopted upon marriage is not always automatically recognized the same way in another country. Upon changing residence, a couple may need to formalize or locally register aspects of their property regime, depending on how each jurisdiction treats the matter.

Owning real estate, accounts or corporate interests in more than one country, coupled with a family's change of residence, tends to complicate determining which law governs any eventual succession. This point is explored in more depth in the context of international succession, but it should already be on the radar at the time of the move, not only when a death occurs.

It is possible for one spouse to become a tax resident of the new country before the other, or for children who remain longer at their original school to retain ties that classify them differently from their parents. Treating the family as a single tax unit is a common and avoidable mistake.

• Assuming custody or travel-authorization documents issued in one country are automatically recognized in the other without any further formality.
• Failing to update a will or succession plan when changing habitual residence.
• Treating the couple's assets as a single unit, without considering how each asset is registered and in which jurisdiction.
• Ignoring the immigration and tax situation of adult children, who may not fall under the same rules as their parents.
• Postponing the formalization of family documents (certificates, powers of attorney, authorizations) until an urgent need arises.

A family that moves to another country carries, in practice, several parallel legal situations — not a single change of address.

1. 01Map the individual immigration situation of each family member, including adult children.
2. 02Review custody, travel-authorization and minor-representation documents in light of the new country of residence.
3. 03Survey how each asset of the couple and family is registered, and in which jurisdiction.
4. 04Reassess or update the will and succession plan in light of the new residence.
5. 05Check the tax-residence criteria applicable to each family member separately.
6. 06Gather and, where necessary, legalize the family documents that may be required in the new country.

Each of these fronts depends on the specific jurisdictions involved — the country pages (/paises/brasil, /paises/portugal, /paises/paraguai) provide additional context on each of them, and the /inteligencia-comparada platform helps visualize differences between regimes. For those with a concrete move already underway, the International Legal Diagnosis at /diagnostico is the starting point for organizing these fronts with a personalized analysis.

International mobility of families requires treating each member and each asset as its own legal situation, even though the family experiences the move as a single event. Planning these fronts in advance costs far less than fixing them after a problem has already taken hold.