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What citizenship by descent means

Some countries treat the children, grandchildren or sometimes great-grandchildren of their citizens as citizens too, even if they were born and live somewhere else. Depending on the country, you may already be a citizen and just need to prove it, or you may need to apply and be registered first.

Each country sets its own rules about how far back it goes. Dates often matter, such as when an ancestor left, or whether they became a citizen somewhere else before the next generation was born.

Citizenship and the passport are two separate steps

First you’re recognized or registered as a citizen. Only then can you apply for that country’s passport, usually online or through its embassy or consulate.

For example, through an Irish grandparent you first join Ireland’s Foreign Births Register, which currently takes about 12 months, and then apply for the passport, which takes about 20 working days more.

You don’t need a passport to start

You’ll need photo ID, but what’s accepted varies. Ireland’s Foreign Births Register asks for a photocopy of your passport, driver’s license or national ID card, certified as a true copy by your witness. Others, such as Italian consulates, ask for a passport. The document list for your country says which.

You’ll still need your own country’s passport to travel home

A second passport doesn’t replace the one from where you live. Most countries expect their own citizens to travel home on their own passport:

• United StatesUS citizens, including dual citizens, must use a US passport to leave and enter the United States.
• CanadaDual Canadian citizens need a valid Canadian passport to fly to Canada. Canadian-American dual citizens can use a valid US passport instead, but should carry proof of their Canadian citizenship.
• United KingdomBritish dual citizens need a valid British or Irish passport to travel to the UK, or another passport with a certificate of entitlement. They can’t use an electronic travel authorization (ETA).
• AustraliaAustralians, including dual nationals, should use their Australian passport to leave and enter Australia.
• New ZealandNew Zealand citizens need a New Zealand passport, or a foreign passport with an endorsement of their New Zealand citizenship, to travel to New Zealand.

So if you don’t have a passport from home yet, you’ll need one as well as your new one when you travel.

You keep your current citizenship

The US, Canada, the UK, Australia and New Zealand all let you hold another citizenship as well as theirs. Most of the countries in this guide do too, but not all. Check “Keep your current passport?” on each country’s guide.

The steps, in order

1. Check if you qualifyThe Do I qualify? checker asks a few yes-or-no questions about your family. “Not sure” is a fine answer: it tells you what to find out.
2. Find out the facts about your ancestorWhere and when they were born, when they left, and whether they became a citizen anywhere else. See finding your ancestor’s records, and note what you find on the family tree worksheet.
3. Order certificatesUsually a full birth certificate for each person in the line, and marriage certificates linking the generations. See ordering certificates.
4. Add apostilles and translations, if neededSome countries want an official stamp, called an apostille, on certificates from other countries, and a translation. See apostilles and translations.
5. ApplyOnline, by mail or at a consulate appointment, depending on the country. Each country’s guide explains how.
6. WaitAnything from a few weeks to well over a year. An Irish passport through a parent born in Ireland takes about 20 working days; Ireland’s Foreign Births Register takes about 12 months on its own.
7. Apply for the passportOnce you’re recognized or registered as a citizen.

The document list builder and the cost and time estimator turn these steps into a plan for your route.

What it costs

Official fees vary a lot. An adult Irish passport applied for online costs €75, plus €15 postage if you live abroad. Italian citizenship costs €600 per adult at a consulate, and it isn’t refunded if you’re turned down. On top come certificates, and apostilles and translations where they’re needed.

Be realistic before you spend money

• Many people find they don’t qualify. Common reasons include an ancestor becoming a citizen of another country before the next generation was born, a line that passed through a woman before that country let women pass on citizenship, or a change in the law. Italy, for example, narrowed its rules overnight in March 2025.
• Find out first, then order. Check the key facts before you pay for certificates. The checker and each country’s guide tell you what to look for.
• Only the country can decide. Nothing on this site can confirm your citizenship. Only that country’s own authorities can.

Do I need to pay someone?

Many people apply themselves, using official websites and the steps above. Some pay for help, especially when records are hard to find or a case has to go to court. This guide doesn’t recommend any service.

Words you’ll meet

Consulate

A country’s office abroad that deals with its citizens and with applications like these. An embassy often has a consular section that does the same.

Full (long-form) birth certificate

The version that shows the parents’ names. The short version usually isn’t accepted.

Certified copy

An official copy of a register entry, issued by the register office. A photocopy, even of an original, isn’t a certified copy.

Apostille

An official certificate attached to a public document, such as a birth certificate, confirming it’s genuine. It’s issued by the country that issued the document.

Sworn translator

A translator officially authorized to produce translations that authorities accept. Some countries keep their own list.

Naturalization

Becoming a citizen of a country by applying, usually after living there. When an ancestor naturalized elsewhere often decides whether citizenship passed down.

More in the plain-English glossary.