Citizenship by Descent: Italian, Irish, EU and UK Routes Explained

Citizenship by descent — also called citizenship iure sanguinis (by right of blood) as distinct from iure soli (by right of birthplace) — is the principle that citizenship passes from parent to child regardless of where the child is born. In many countries, this principle extends across multiple generations: not just parent to child but grandparent to grandchild, or even further back.

For internationally mobile families with European heritage, citizenship by descent can deliver a passport as powerful as any citizenship by investment programme — at a fraction of the cost, and in many cases for free beyond the legal and documentary preparation fees. The strategic prize for non-EU nationals with European ancestry is EU citizenship: the right to live, work, and establish residency in any of the 27 EU member states, now and in perpetuity.

This guide covers the principal descent-based citizenship routes relevant to HNW internationally mobile individuals: Italy, Ireland, the UK, and other European programmes.

What Citizenship by Descent Means

Under ius sanguinis, citizenship passes from a citizen parent to a child at the moment of birth. The child acquires citizenship automatically — no application is needed to create the entitlement, only to have it recognised and documented.

Different countries impose different limits on how far back this principle extends:

• Some countries (like Ireland) allow citizenship to be claimed by those with a grandparent who was born in the country, but no further without additional requirements
• Italy historically allowed the descent chain to go back indefinitely in the male line, but from 2025 has restricted automatic recognition to those with an Italian-born parent or grandparent (see below)
• Others (like the UK) limit transmission after one generation born abroad

The practical challenge is documentation: proving the chain of descent requires birth, marriage, and death certificates for each generation in the chain, apostilled and in many cases translated. For chains stretching back four or five generations, this is a significant research and administrative exercise.

Italian Citizenship by Descent (Cittadinanza per Discendenza)

Italy's citizenship by descent programme is arguably the most valuable — and the most generous in geographic scope — of any European country's programme. It has attracted enormous interest particularly from Americans, Australians, Canadians, Brazilians, and Argentinians (all countries with large Italian diaspora communities), and more recently from UK nationals seeking EU citizenship post-Brexit.

The Basic Rule

An Italian citizen's child acquires Italian citizenship at birth, wherever born. Historically this principle applied in the male line without a generational limit: if your great-great-grandfather was Italian and never renounced his Italian citizenship before the birth of the child through whom you descend, you were potentially Italian.

This changed in 2025. Decree-Law 36/2025, converted into Law 74/2025 (the "Tajani decree"), introduced a two-generation limit for the recognition of citizenship by descent. Under the new rules, a person born abroad is recognised as an Italian citizen by descent only if at least one parent or grandparent was born in Italy (subject to limited exceptions). Applications that had already been lodged at a consulate, comune or court — or for which an appointment had been notified — by 27 March 2025 continue to be processed under the old, unlimited rules. The Italian Constitutional Court considered challenges to the decree in 2026 and the restrictions remain in force. The previously common great-grandparent or great-great-grandparent claim is therefore no longer available through the standard administrative route for new applicants.

For descendants through the female line, the position was more complex historically: before 1948, Italian law did not automatically transmit citizenship through mothers. Italian courts have progressively resolved this, allowing female-line transmission claims to be made before Italian courts (typically in Brazilian courts for Brazilian applicants with Italian female-line ancestors, or before Italian courts for other applicants). This is a litigated rather than administrative route for female-line claims.

Key Conditions

Two-generation limit (from 2025): under Law 74/2025, the qualifying Italian-born ancestor must be a parent or grandparent. Claims through a great-grandparent or earlier ancestor are no longer recognised through the standard administrative route for applications lodged after 27 March 2025.

Non-renunciation: the Italian ancestor must not have naturalised in another country before the birth of the next generation in the chain. For Americans with Italian ancestors, the critical question is: when did the Italian ancestor naturalise as American? If the ancestor naturalised before the birth of the relevant child, the citizenship chain is broken at that point.

1948 rule for female line: as above — female-line descent before 1948 requires a court application rather than the standard administrative route.

Legal status of the documents: all birth, marriage, and death certificates must be apostilled and certified translations provided.

The Application Process

Applications are made either at the Italian consulate with jurisdiction over the applicant's country of residence, or directly in Italy at the comune (municipality) of the Italian ancestor's origin.

Consulate route: typically requires booking an appointment — waiting times at major Italian consulates (New York, Buenos Aires, São Paulo) stretch to years. Some applicants choose to travel to Italy and apply at the Italian comune of ancestral origin, which typically processes the application faster (some comuni complete the process within 30-90 days for applicants who relocate temporarily to Italy for the purpose).

The resulting document is registration in the Italian registry and issue of an Italian passport — a top-tier EU passport with access to all EU member states, approximately 191 visa-free destinations globally, and full EU citizenship rights.

Strategic Value Post-Brexit

For UK nationals with Italian ancestry, Italian citizenship by descent provides the EU citizenship that Brexit removed. An Italian-British dual national has the right to live and work in all 27 EU member states, to pass that right to their children, and to hold a passport that travels more freely within Europe than the UK passport alone.

Irish Citizenship by Descent

Ireland has one of the most accessible citizenship by descent routes among EU countries.

The Foreign Births Register

If one of your grandparents was born on the island of Ireland — either the Republic of Ireland or Northern Ireland — you are entitled to Irish citizenship regardless of where your parents and you were born. You claim this by registering on the Foreign Births Register maintained by the Irish Department of Foreign Affairs.

Unlike many other citizenship by descent routes, the Irish scheme does not require you to prove your parent or parents are Irish citizens — the grandparent's birth in Ireland is sufficient to establish your entitlement, provided your parent did not register on the Foreign Births Register before your birth (in which case your citizenship passes through the parent's registration, not directly from the grandparent).

For individuals who are not yet registered, applying to the Foreign Births Register is the first step. Processing typically takes one to two years given the volume of applications (which has increased significantly since Brexit). Once registered, an Irish passport can be applied for.

Passing Irish Citizenship to Your Own Children

Once you are registered on the Foreign Births Register, your Irish citizenship can be passed to your children — provided they are registered before or at the time of their birth, or by registering them on the Foreign Births Register themselves.

An important limitation: the citizenship can only pass one further generation automatically through the Foreign Births Register if the parent registers before the child's birth. If the parent is registered after the child is born, the child must register independently on the Foreign Births Register in their own right. This subtlety matters for families who discover their Irish entitlement after children have already been born.

Strategic Value

An Irish passport is one of the most versatile in the world: EU citizenship, Schengen access, Commonwealth access, and — uniquely — Ireland is not in the Schengen Area but has a separate Common Travel Area arrangement with the UK, meaning Irish citizens retain relatively free movement between the UK and Ireland regardless of Brexit. For a UK-based family with Irish descent, Irish citizenship preserves the pre-Brexit EU freedom that the UK passport no longer provides.

UK Citizenship by Descent

British citizenship can pass from a British parent to a child born abroad — but only one generation.

A child born outside the UK to a British citizen parent acquires British citizenship by descent automatically at birth. That child is British. However, their own children born outside the UK are generally not automatically British — citizenship by descent does not automatically transmit to the next generation born outside the UK (with limited exceptions relating to British nationals in Crown service).

This "transmission gap" is a significant limitation compared to Italian or Irish law, which (in different ways) allow descent to continue further. The practical implication:

• A child born in Australia to a UK-born British parent: British citizen
• That child's children born in Australia to the Australia-born British citizen: generally not automatically British (unless the parent registers the child under the British Nationality Act provisions before their birth, which requires specific Crown service or qualifying employment circumstances)

For families with British ancestry who are two or more generations removed from a UK-born ancestor, British citizenship by descent is typically not available and the route to a British passport is either naturalisation after qualifying UK residence or a different ancestral route if available.

Other European Descent Programmes

Polish Citizenship by Descent

Poland allows citizens to claim citizenship for descendants of Polish citizens in circumstances where the Polish ancestor was a Polish citizen at the time of the child's birth and the citizenship was not expressly relinquished. The chain can extend across generations. Poland has a significant diaspora in the UK, US, Canada, and Australia. The process requires research into Polish civil records.

Romanian and Bulgarian Citizenship

Both Romania and Bulgaria allow descendants of Romanian and Bulgarian nationals to recover citizenship. Particularly relevant for Sephardic Jewish families historically associated with these territories and for the families of post-WWII emigrants. Both countries are EU members; the citizenship delivers the same EU rights as Italian or Irish citizenship.

Hungarian Citizenship

Hungary offers citizenship to descendants of Hungarian nationals who were Hungarian citizens before losing citizenship by emigration or through historical border changes. Hungary is an EU member and the passport is EU-capable. The process involves registration with Hungarian consular authorities.

Portuguese and Spanish Citizenship by Descent and Heritage

Portugal and Spain have specific heritage programmes for descendants of Sephardic Jews expelled during the Inquisition, as well as standard descent routes for nationals' descendants. Processing times and requirements vary.

The Documentation Challenge

The common challenge across all descent-based citizenship routes is documentation. For a chain of three or four generations, you may need:

• Birth certificates for each person in the chain
• Marriage certificates for each marriage in the chain
• Death certificates where needed to establish dates relative to other events
• Where required: proof of non-naturalization (or date of naturalization) of the immigrant ancestor
• Apostilles on all documents issued by countries that are party to the Hague Apostille Convention
• Certified translations for all documents not in the language of the target country

Records may be held in church archives, civil registration offices, consular archives, or — for older records — in archives that require specialist research. Professional genealogists who specialise in the target country's records are often essential for chains stretching back to the nineteenth century.

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Citizenship by descent rules vary by country, change over time, and depend on the specific facts of each family's history. This guide provides a general overview only. All citizenship claims should be verified with specialist immigration lawyers in the relevant countries before preparing and submitting an application. Processing times quoted are indicative and subject to significant variation.

How Global Investments Can Help

Global Investments assists internationally mobile families in identifying and pursuing citizenship by descent opportunities across Italian, Irish, and other European programmes. We work with specialist genealogists and immigration lawyers in each country to prepare the documentary chain, manage the application process, and coordinate the resulting citizenship with the family's broader passport and residency strategy. Contact our team for a confidential assessment of your ancestry and citizenship options.