After you’re approved: what to do once your citizenship by descent comes through

An approval letter isn’t the last step. In most countries you still have to take an oath or collect a certificate, get your own birth (and marriage) entered in the national civil register, and apply separately for a passport. Some countries then give you an ID number, and several attach deadlines that decide whether you, or your children, keep the citizenship. This page collects what our country guides say about each step. Where a guide doesn’t cover a topic, we say so rather than fill the gap.

Checklist: the first year after approval

1. Collect your decision or certificate, and take the oath if your country requires one.
2. Get your birth, and any marriage, recorded in the country’s civil register.
3. Get your national ID number, where the country issues one.
4. Apply for your passport (and ID card, if you want one).
5. Register with your consulate if your country expects it.
6. Note any deadline that can cost you or your children the citizenship.
7. Register any children who can claim through you, before their own deadlines.

From approval to passport, country by country

These are the guides that spell out what you receive and what comes next. For the other countries, the country guide covers the claim itself but not the steps afterwards in detail.

Several more guides give the short version: in Slovenia, Bosnia and Herzegovina and Albania you are entered in the register of citizens and then apply for a passport; in San Marino, once your declaration is recorded; in Belgium, you register with the consulate and apply. Where citizenship comes from a parent at birth, as in Ireland with an Irish-born parent or the UK for people already British by descent, there is nothing to approve: you apply for the passport as your proof.

The oath or ceremony

Routes that recognise citizenship you already hold usually have no oath. Routes that grant citizenship often do, and some set a deadline for it:

• UK, Form UKM: you become British at the ceremony, which you must attend within 90 days of your invitation. Section 4C applicants pay only the £130 ceremony fee. See British citizenship through your mother.
• Hungary: you become Hungarian on the day you take the oath or pledge, at the mission or Hungarian town you chose on the form. See simplified naturalization.
• Romania: approval is followed by an oath of allegiance before you get Romanian documents.
• Croatia: a solemn oath to respect the Constitution and laws (Article 24b). See Croatian citizenship under Article 11.
• Spain: for grants under article 21, you have 180 days from notification to take the oath and meet the other article 23 requirements, or the grant lapses. See Spanish citizenship through grandparents.
• Greece, omogenis naturalisation: if approved, you take an oath within one year.
• No oath: the Czech § 31 declaration has no oath; Poland’s confirmation and Ireland’s Foreign Births Register recognise or register citizenship without one.

Getting your passport

The passport is a separate application in every guide that covers it. A few points from the guides:

• Ireland: you can’t apply until you hold your Foreign Birth Registration certificate. The adult 10-year passport is €75 online plus €15 postage abroad, a first one averages 20 working days, and first-time applications can’t be expedited, so don’t book travel until it arrives. If your documents haven’t reached the Passport Service within 20 weeks, it may decide on what it has. Full steps: Irish passport through grandparents.
• Czech Republic: a first passport at an embassy costs CZK 2,400 from age 15 (CZK 400 under 15). In Los Angeles it needs your Czech birth certificate, proof of citizenship and an in-person appointment. See Czech citizenship by declaration.
• Poland: where the transcription of your birth is tied to the citizenship case, the passport application is accepted only after a positive confirmation decision. Each living descendant needs their own decision for a passport. See Polish citizenship confirmation.
• Hungary: your Hungarian can be checked again later in the process, for example when you apply for a passport.
• UK: the passport is a separate fee to HM Passport Office, and once you have one, GOV.UK says you must use it to enter the UK.

Registering your birth and marriage

Before you can get a passport, most countries need your own birth, and usually your marriage, in their civil register. The guides describe it like this:

• Czech Republic: births and marriages of Czech citizens abroad are recorded in the Special Registry (Zvláštní matrika) at the Brno-střed Municipal District Office, including after citizenship by declaration.
• Poland: your foreign birth certificate is transcribed (transkrypcja) into the Polish civil register.
• Romania: you transcribe your birth certificate after the oath; a child of a Romanian parent only needs the foreign birth transcribed.
• Hungary: the forms to register your birth, and any marriage or divorce, go in with the naturalization application.
• Greece: since Law 4674/2020, citizens abroad declare births, marriages and deaths to the Greek consulate; births declared at consulates from 1 January 2022 no longer need transcribing in the Special Registry in Athens. Each registration is separate, often with its own appointment and fee. See Greek municipal registration.
• Spain: the consulate registers the birth in the Spanish Civil Registry (inscripción de nacimiento).

The same documents you used for the claim usually serve here, so keep the apostilled, translated set together. Our documents checklist and translation guide cover what each authority tends to ask for.

National ID numbers

Only a few guides go into this, but where they do the number comes before the passport:

• Poland, PESEL: for someone born abroad with no registered Polish address, a Polish birth certificate from transcription is a precondition for a PESEL number.
• Hungary: after the oath you’re registered with a Hungarian personal identification number. Fingerprints, signature and photo for a future Hungarian ID card are taken at the application appointment.
• Latvia: once registered, you’re entered in the Population Register and given a personal identity number, which you need before applying for a passport. See Latvian citizenship for exiles’ descendants.
• Spain: once your birth is inscribed you can request a DNI, the national identity document.
• Cyprus and Greece: after approval or registration you can apply for an ID card as well as a passport.

Consular registration and voting

Consular registration. Spain’s guide lists registering with your consulate (matrícula consular) as a step after your birth is registered; Belgium’s says to register with the Belgian consulate and apply for a passport; Italian citizens abroad are entered in AIRE, the Registry of Italians Abroad. In France, consular registration also matters for the future: it is one of the things that counts as possession d’état of French nationality, and a French line that goes more than fifty years abroad without any of it can lose the ability to prove nationality by descent. See the French 50-year rule.

Voting. None of our country guides explains how to register to vote from abroad, so we don’t set out rules here. France’s guide counts voting among the acts that keep possession d’état alive. Ask your consulate how overseas voting works for your country.

Keeping your citizenship: deadlines and loss rules

Approval doesn’t always mean permanent. The guides flag these rules, which apply after you hold the citizenship:

• Age 22 in the Nordic countries. Dual citizens born abroad must apply to retain Swedish, Danish, Norwegian or Icelandic citizenship before 22, or have enough ties. In Finland, a passport or ID application, military or civil service, or a written notification before 22 keeps it. Denmark’s retention application costs DKK 1,200 and must be filed between 20 and 22.
• Age 28 in Belgium. If you were born abroad after 1 January 1967 and hold another nationality, keep the link between 18 and 28: for example get a Belgian passport or ID card, or sign a retention declaration at a consulate.
• Age 25 in Switzerland. A dual citizen born abroad whose birth was never reported loses Swiss citizenship at 25.
• 13 years in the Netherlands. Dutch dual nationals who live outside the Netherlands and the EU for 13 consecutive years without renewing a Dutch passport or ID card, or obtaining a Declaration of Possession of Dutch Nationality, lose it automatically.
• Taking another nationality later. A Slovak citizen who voluntarily acquires a foreign nationality loses Slovak citizenship, with exceptions. A Lithuanian citizen who acquires another citizenship outside the listed cases loses Lithuanian citizenship and must notify within 2 months (see Lithuanian dual citizenship). A Monégasque who voluntarily takes another nationality loses Monégasque nationality.

The full country list is in dual citizenship by descent, country by country.

Passing citizenship to your children

This is where timing matters most. A child born before your citizenship takes effect may not be covered, and some countries need the child registered by a set age. From the guides:

• Ireland: only children born after you were entered on the Foreign Births Register can register through you (unless the registration was made before 1 July 1986). If you’re planning a family, register first. See Irish citizenship through great-grandparents.
• United Kingdom: a British citizen by descent, including someone registered under section 4C, generally can’t pass citizenship to children born outside the UK. Guide UKM notes that naturalising while living in the UK gives citizenship otherwise than by descent, which can pass to children born abroad after that. Two narrow child registrations, sections 3(2) and 3(5), must be used before the child turns 18.
• Germany: since 2000, a German born abroad who lives abroad passes citizenship to a child born abroad only if the child’s birth is registered with the German authorities within a year (§ 4(4) StAG).
• Italy: article 4(1-bis) lets the parents of a minor whose parent is a citizen by birth declare within three years of the birth, or have the child acquire citizenship after two continuous years’ legal residence in Italy. See Italian citizenship through great-grandparents.
• Czech Republic: children born after you become Czech are Czech by birth (Section 4), and their birth is registered in Brno. A parent can make a separate declaration for a child under 18 who is the child or grandchild of a former citizen.
• Luxembourg: a child under 18 becomes Luxembourgish when their parent obtains nationality through an option (Article 2). See Luxembourg Articles 7 and 23.
• Latvia: your children under 15 can be registered with you.
• Poland: if you attach a parent’s confirmation decision (or Polish passport or ID), your child’s application skips the part of the form about grandparents.
• Spain and Romania: a child born to a Spanish parent is Spanish by origin and the birth is registered at the consulate; a child born to a Romanian parent only needs the birth transcribed.
• Registration deadlines: Slovenia (parents register the child before 18), North Macedonia (before 18, or by the child’s own application between 18 and 23), Montenegro (before 18, or by yourself before 23 if you don’t hold the other parent’s citizenship), Bosnia and Herzegovina (registered before 23) and San Marino (a declaration before 25 with one Sammarinese parent).

Military service

Only a few guides raise it. Where they do:

• Greece: once registered, a man is a Greek citizen with a military obligation from 19 to 45. Those who live permanently abroad can get a deferral through a consular certificate of permanent residence abroad. If you plan to move to Greece, ask about military status before you register. See Greek citizenship through grandparents.
• Belarus: Belarusian men are subject to military obligations; the guide says to check the implications before confirming or acquiring citizenship.
• Finland: Finnish military or civil service is one of the steps that keeps citizenship for a dual citizen born abroad under the age-22 rule.

Our other country guides don’t set out military-service rules. Ask the country’s consulate.

Tax

None of our country guides covers tax, and we don’t give tax advice. Whether becoming a citizen changes anything for you depends on national law and any treaty between the countries involved, so take questions to the tax authorities themselves or a qualified adviser. Official starting points:

• Your Europe (European Union): taxes explains that there are no EU-wide rules on how people living or working abroad are taxed, and links to each country’s tax administration.
• Internal Revenue Service: US citizens and resident aliens abroad for readers who are US citizens.

Still working on the claim itself? See how long citizenship by descent takes, what it costs, or run the free eligibility checker.

Frequently asked questions

Official sources

Each country guide linked on this page lists its own official sources. The main ones behind this page:

• Office of Citizenship and Migration Affairs (Latvia): Latvian exiles and their descendants (Population Register entry and identity number on registration)
• Home Office: immigration and nationality fees from 8 October 2026 (£130 citizenship ceremony)
• GOV.UK: apply for citizenship if you have a British parent, born before 1983
• Mazowiecki Urząd Wojewódzki: confirmation of Polish citizenship
• Brno-střed Municipal District Office: Special Registry, registering a birth abroad
• Department of Foreign Affairs (Ireland): registering a foreign birth
• Consulate General of Hungary, Toronto: simplified naturalization
• Greece in Australia: vital records
• Your Europe: taxes and IRS: US citizens and resident aliens abroad

Checked against these sources on 29 October 2026. The Latvian, UK fee, Polish, Your Europe and IRS pages were read directly on that date; the Irish Department of Foreign Affairs pages blocked automated access. Every other country step on this page is as stated in the linked country guide, which gives its own sources and check date. Procedures change, and only the country’s authorities can tell you what applies to you; confirm with your consulate before you rely on a deadline.