A grandparent born in Ireland is usually enough. The register, not the ancestry, is the constraint.
EU member stateDual nationality generally permittedComplexity
The clearest route in Europe and the one most often overlooked. Irish citizenship carries EU freedom of movement, and the entitlement is generally established rather than discretionary — you are registering an existing citizenship, not applying for a favour.
Why claims fail hereThe generational chain has to be registered in sequence. If your parent was not entered on the Foreign Births Register before you were born, your own claim through a great-grandparent is usually lost — which is why a parent registering first is often the whole plan.
Documents to look for (4)
- Grandparent’s Irish birth certificate (or, failing that, baptismal record)
- Parent’s birth certificate and marriage certificate
- Your own birth certificate, and marriage certificate if your name has changed
- Proof of identity: passport, plus two documents showing address
Also worth knowing- Irish citizenship by descent is generally not lost by holding another nationality.
- Once registered, you can pass citizenship to children born afterwards — but only if you register before their birth.
IT
Italy
No generational limit in principle, subject to recent restrictionsVaries enormously: months at a consulate, years through a court
Historically unlimited generations — but the 1948 rule and the 2025 restrictions make the dates decisive.
EU member stateDual nationality generally permittedComplexity
Italy has no generational cap in principle, which is why claims through a great-great-grandparent sometimes succeed. At its best it is the most generous descent regime in Europe.
Why claims fail hereTwo dates decide almost every Italian case. First, before 1 January 1948 a woman could not pass citizenship to her children — so a maternal link across that date is a different, harder argument. Second, 2025 changes narrowed jure sanguinis substantially, generally requiring a parent or grandparent born in Italy and evidence of a genuine link. Cases that were routine in 2023 are not routine now.
Documents to look for (4)
- Ancestor’s Italian birth record (estratto dell’atto di nascita)
- Proof of the ancestor’s arrival and any naturalisation — or a certificate of non-naturalisation
- Every birth and marriage certificate down the line, with apostilles and translations
- Consular registration records where they exist
Also worth knowing- Before 1992, voluntarily taking another citizenship was generally treated as renouncing Italian citizenship — the single most common reason a claim fails.
- Where the consulate cannot help, claims are sometimes pursued through the Italian courts, which is a materially different cost and timeline.
- Fees, consular backlogs and judicial routes change; the 2025 reform is still being interpreted.
DE
Germany
Varies by route: §5 descent, §15 restoration, §116 Basic LawTypically 1–3 years; §116 cases can be longer
Three separate legal routes — descent, restored citizenship for Nazi-era persecution, and the 2021 gender-equality fix.
EU member stateDual nationality generally permittedComplexity
Germany runs several distinct schemes, and which one applies changes everything. Section 116 of the Basic Law covers people who were deprived of citizenship or never acquired it for political, racial or religious reasons between 1933 and 1945 — including their descendants. Section 15 restores citizenship to those who gave it up under Nazi pressure. Section 5 covers ordinary descent, including claims that previously failed because only fathers could pass citizenship before 1975.
Why claims fail herePeople assume they have one claim when in fact the right route is a different one — or that the persecution route is closed because the family left long ago. It is precisely designed for descendants. Conversely, ordinary §5 descent through a pre-1975 maternal line only became possible relatively recently, and only if the child would otherwise be stateless.
Documents to look for (4)
- German birth or citizenship records of the ancestor
- Emigration and naturalisation records in the destination country
- For §116: evidence of persecution or of the denial of citizenship
- Certificates for every generation between the ancestor and you
Also worth knowing- German law now permits dual nationality more broadly than it once did, but the rules differ by route.
- These are technical applications; the consular and federal office processes are unforgiving about documentation gaps.
No stated generational limit, but the outcome usually turns on which border moved.
EU member stateDual nationality generally permittedComplexity
Poland recognises citizenship as continuing through the generations, and the procedure is a confirmation rather than a discretionary grant — which is a meaningful distinction when you are dealing with a bureaucracy.
Why claims fail hereBorder history does the work here. Ancestors from territory that was Polish at the relevant date, then German, Lithuanian, Ukrainian or Belarusian, present a different evidentiary problem from ancestors from the current Polish state. Recent practice has also become stricter about proving an unbroken link.
Documents to look for (4)
- The ancestor’s Polish birth or baptism certificate
- Records showing when and where they left
- Any military, land or census records that place them in Polish territory
- Certificates for every intervening generation
Also worth knowing- A 1951 treaty with the Soviet Union affects some claims from the eastern territories.
- Confirmation procedures are handled by consulates and, in some cases, by Polish administrative bodies.
Descent through a Hungarian ancestor, usually with a language requirement attached.
EU member stateDual nationality generally permittedComplexity
Hungary offers a simplified naturalisation for people who can demonstrate Hungarian ancestry rather than current Hungarian residence — unusual in the EU, and it does not require you to move.
Why claims fail hereThe simplified route generally expects some Hungarian language ability at interview, which is the step most applicants underestimate. Documentary requirements for the ancestor are also strict, and a chain of birth certificates in the right form is essential.
Documents to look for (4)
- The ancestor’s Hungarian birth or baptism record
- Records establishing the family link across generations
- Evidence of any prior Hungarian citizenship
- For the simplified route, evidence of Hungarian language competence
Also worth knowing- The interview stage is real and has been reported as increasingly exacting.
- Processes and political posture toward the scheme have changed over time.
Direct to children; grandchildren via a declaration with a demonstrated tie.
EU member stateDual nationality generally permittedComplexity
Portugal combines descent with one of Europe’s more functional naturalisation paths, and the passport is genuinely useful for mobility. For the right family, it is the strongest single outcome on this site.
Why claims fail hereThe Sephardic-descendant route that dominated headlines was substantially narrowed, and much published guidance still describes it as open. If that is the basis of your interest, it needs immediate re-checking. The grandchild route also turns on a declaration and evidence of an effective tie to Portugal, not merely a birth certificate.
Documents to look for (4)
- The ancestor’s Portuguese birth or baptism record
- Portuguese civil registry entries for the intervening generation where they exist
- Your own full chain of certificates, apostilled
- Evidence of connection to Portugal for grandchild claims
Also worth knowing- Portuguese nationality law has been amended repeatedly; the version that applies to you depends on the date of the relevant events.
- Processing runs through central registries and consulates with significant backlogs.
Children of Spanish nationals by right; grandchildren via the exile provisions of the memory law.
EU member stateDual nationality generally permittedComplexity
Spain’s democratic-memory legislation opened a path for grandchildren of people who lost or were forced to renounce Spanish nationality for political reasons — a route that is unusual in being explicitly about descendants rather than the individual.
Why claims fail hereThe exile-based route is framed around a specific historical harm and requires evidence of that harm, not simply Spanish ancestry. It has also been subject to deadline extensions, which means published closing dates are unreliable in both directions. Ordinary grandchild claims outside those provisions are much narrower than most guides imply.
Documents to look for (4)
- The ancestor’s Spanish birth certificate and consular registration records
- Evidence of exile or of nationality lost for political reasons
- The full certificate chain to you, legalised or apostilled
- Certificates of any prior nationality held
Also worth knowing- Spain has historically been restrictive about dual nationality outside certain countries and agreements.
- Deadlines for the memory-law routes have been extended more than once; confirm the current position before relying on it.
Restoration for descendants of people who fled or were expelled under the Nazi regime.
EU member stateDual nationality generally permittedComplexity
Austria’s route is explicitly restorative: it exists for people whose ancestors lost Austrian citizenship by fleeing persecution, and it extends to descendants rather than requiring the original victim to apply.
Why claims fail hereIt requires evidence of the persecution and of residence or citizenship in Austria before the flight — not simply an Austrian-sounding surname or a family story. The applicant’s own prior nationality does not usually block it, which is the good news; the evidentiary burden is the hard part.
Documents to look for (4)
- Proof of the ancestor’s Austrian citizenship and residence before departure
- Documentation of the flight or expulsion, and of any loss of citizenship
- Birth and marriage records down the line
- Identity documents for the applicant
Also worth knowing- Austria has historically restricted dual nationality, but the restoration route has been designed with descendants abroad in mind.
- Some applications are made from abroad through the embassy rather than by relocating.
Claims up to the third degree — generally a great-grandparent.
EU member stateDual nationality generally permittedComplexity
Romania allows reacquisition along a defined line of kinship and, importantly, does not require you to give up what you already hold. The rule for territory lost during the Soviet period is a distinct and often overlooked basis.
Why claims fail hereThe generational limit is real and enforced. Claims through a great-great-grandparent generally fail, and the birth-date arithmetic in the chain has to be exact. Documentary standards for the ancestor’s Romanian birth or the relevant territorial connection are strict.
Documents to look for (4)
- The ancestor’s Romanian birth certificate, or evidence of birth in the relevant territory
- Documentation of the territorial history where the claim depends on it
- The full chain of certificates with apostilles and certified translations
- Criminal-record certificate and identity documents
Also worth knowing- Different rules apply to former territories than to the present-day state.
- The authority processes files in order and publishes little about timing.
Restoration for people who lost citizenship during the 1940–1990 occupation.
EU member stateDual nationality generally permittedComplexity
Lithuania frames this as restoration, and it reaches descendants of people who left or were displaced while the country was occupied — a far wider net than a plain ancestry test.
Why claims fail hereThe claim turns on the ancestor having been a Lithuanian citizen at the relevant moment and having lost it through the occupation, not on general ethnic Lithuanian heritage. Emigration date evidence — ship manifests, displaced-persons records, Soviet-era documents — is often the deciding material.
Documents to look for (4)
- The ancestor’s Lithuanian birth, baptism or citizenship record
- Evidence of the date and circumstances of departure
- Displaced-persons or refugee documentation where applicable
- The certificate chain down to the applicant
Also worth knowing- The law distinguishes restoration from ordinary naturalisation, with different consequences.
- Lithuania permits multiple nationality in defined circumstances, not universally.
A comparatively deep statutory reach — up to the fourth generation, with a declaration.
EU member stateDual nationality generally permittedComplexity
Slovakia’s statutory reach is unusually deep for the EU, and the procedure is a declaration with supporting documents rather than a discretionary administrative decision.
Why claims fail hereThe declaration route has been amended more than once, and the version in force when your ancestor left can matter as much as the current one. Documentation of the ancestor’s Czechoslovak or Slovak citizenship, not merely birth in the territory, is the usual sticking point.
Documents to look for (4)
- The ancestor’s birth or baptism certificate from the relevant territory
- Evidence of Czechoslovak or Slovak citizenship
- Records of departure and any subsequent naturalisation
- Certificates for every generation, with translations
Also worth knowing- Czechoslovak-era records are split between Slovak and Czech archives and occasionally both.
- The declaration procedure requires an in-person step in some cases.
Narrower than Slovakia — generally a parent or grandparent, with options for emigrants.
EU member stateDual nationality generally permittedComplexity
There are specific provisions for people who lost Czechoslovak citizenship by emigration, and for their descendants, which survive in Czech law even where the general route is narrow.
Why claims fail hereCzech practice is generally stricter than Slovak on the number of generations, and the emigration provisions require you to show the loss of citizenship happened in a way the law recognises. Assuming the Slovak outcome because the family came from the same region is a frequent and expensive mistake.
Documents to look for (4)
- The ancestor’s Czechoslovak or Czech citizenship records
- Evidence of emigration and of the loss of citizenship
- Birth, marriage and death certificates down the line
- Proof of current nationality and residence
Also worth knowing- Czechia and Slovakia inherited the same 1918–1992 body of law but diverged after the split.
- Language and integration conditions can apply to some routes but not others.
Genuinely generous in principle, administratively difficult in practice.
EU member stateDual nationality generally permittedComplexity
Greek nationality law has long allowed descent to pass through generations, and for the right family — particularly those with records in a specific village or island — it produces a full EU passport from ancestry alone.
Why claims fail hereGreece requires registration with the municipal roll (dimotologio) and the consulate, and the record-keeping is fragmented. Where a link was never registered, claims can require court proceedings in Greece. Published guidance rarely reflects how much of this work happens in person and in Greek.
Documents to look for (4)
- The ancestor’s Greek birth registration or dimotologio entry
- Marriage and baptism records from the municipality of origin
- Evidence of the ancestor’s Greek nationality
- Certificates down the chain, translated and legalised
Also worth knowing- Some routes require the claim to be registered within a timeframe of a triggering event.
- Practitioners are usually needed in Greece itself, not only at a consulate.
Descent with a defined kinship line, plus specific provisions for the diaspora.
EU member stateDual nationality generally permittedComplexity
Croatia recognises the diaspora explicitly in its nationality law, and the EU accession in 2013 means the resulting passport carries full freedom of movement.
Why claims fail hereThe kinship limit and the evidence of Croatian ethnic affiliation both have to hold up. Records from the pre-Yugoslav and Yugoslav periods sit in different archives, and the correct archive for your family is not always obvious from the place name.
Documents to look for (4)
- The ancestor’s birth, baptism or citizenship record
- Evidence of Croatian ethnicity or affiliation where required
- The certificate chain to the applicant
- Proof of current citizenship
Also worth knowing- Requirements for diaspora applicants differ from those for people living in Croatia.
- Yugoslav-era documentation is accepted but must be read correctly.
Origin-based route requiring documentary proof of Bulgarian ancestry.
EU member stateDual nationality generally permittedComplexity
Bulgaria has a specific origin-based procedure distinct from ordinary naturalisation, and it does not require prior residence — which makes it relevant to people with no intention of moving.
Why claims fail hereThe evidentiary standard for "Bulgarian origin" is the whole case, and it is assessed by a state agency rather than a consular officer. A single missing generation in the certificate chain usually stalls the file indefinitely rather than producing a refusal you can appeal.
Documents to look for (4)
- Birth or baptism records establishing Bulgarian ancestry
- The full certificate chain, apostilled and translated into Bulgarian
- A certificate of Bulgarian origin issued through the prescribed process
- Identity and criminal-record documents
Also worth knowing- The origin certificate is a separate administrative step that precedes the nationality application.
- Processing is centralised and correspondence is generally in Bulgarian.
Difficulty reflects the technical and evidentiary burden, not the value of the passport. A complexity-5 file is not a worse outcome than a complexity-2 one; it is a longer, more expensive engagement that usually needs counsel on the ground.