Most Western democracies now allow multiple citizenship without restriction. The United States, United Kingdom, Canada, Australia, France, Ireland, Portugal, and (since June 2024) Germany all sit in this group, along with dozens of others. A second set of countries permits dual nationality only through treaties or narrow exceptions, and a smaller but significant group (China, India, Japan, Singapore, Saudi Arabia, the UAE, and others) prohibits it outright. If you’re weighing a naturalization, an ancestry claim, or simply trying to keep the passport you already hold, the rules on countries that allow multiple citizenship depend on which passports are involved and, increasingly, on when you apply.
Countries That Allow Multiple Citizenship Without Restriction
In these countries you can naturalize elsewhere, or hold a foreign nationality from birth, without losing your original citizenship.
The United States is one of the most permissive. The State Department’s position is that “a U.S. citizen may naturalize in a foreign state without any risk to their U.S. citizenship.”1U.S. Department of State. Dual Nationality Americans can hold multiple passports and keep full domestic legal standing.
The United Kingdom says the same in plainer terms: “You can be a British citizen and also a citizen of other countries. You do not need to apply for dual citizenship. You can apply for foreign citizenship and keep your British citizenship.”2GOV.UK. Dual Citizenship The British Nationality Act 1981 imposes no cap on the number of citizenships a British person can hold.3Legislation.gov.uk. British Nationality Act 1981
Canada permits multiple citizenships and requires no special permit; Canadians who acquire a foreign passport remain citizens unless they go through a formal renunciation.4Government of Canada. Dual Citizens5Immigration, Refugees and Citizenship Canada. What Is Dual Citizenship
Australia joined the club in 2002, when the Australian Citizenship Amendment Act ended automatic loss of citizenship for Australians naturalizing abroad. France has recognized dual citizenship since 1973 and does not require applicants to renounce a prior nationality. Portugal permits multiple citizenship on similar terms.
Ireland allows dual citizenship and is especially useful for people with Irish heritage. If a grandparent was born on the island of Ireland, you can claim Irish citizenship through the Foreign Births Register.6Department of Foreign Affairs. Citizenship Registration typically takes about 12 months once the government has all required documentation, which includes original birth and marriage certificates for you, your Irish-citizen parent, and your Irish-born grandparent.7Department of Foreign Affairs. Registering a Foreign Birth
Recent Changes You Need to Know About
Germany Opened the Door in June 2024
Germany used to be one of the strictest major economies on dual nationality. Germans who naturalized abroad lost their citizenship unless they had a special retention permit, and foreigners naturalizing in Germany had to renounce their prior citizenship.
That ended on June 27, 2024. Under the reformed Nationality Act, German nationals can now acquire any foreign citizenship without losing their German one, and the Federal Foreign Office confirms that “it is therefore no longer necessary to seek permission to retain a nationality.”8Federal Foreign Office. Germany’s Nationality Law – Significant Changes People born in Germany with multiple citizenships under the old birthright rules no longer have to choose between them.
Italy Tightened Descent Claims in 2025
Italy moved the other way. For more than a century, Italian citizenship by descent had no generational limit, and claimants routinely traced ancestry back four or five generations. In March 2025, Decree-Law No. 36/2025 imposed a two-generation limit. Citizenship can now transmit only if the parent resided in Italy for at least two years, or if the grandparent was born in Italy. The Italian Constitutional Court upheld the reform in March 2026, holding that the Constitution “does not require the State to recognise Italian citizenship for all descendants of Italian citizens without generational limits.” Applications filed before March 28, 2025 are still processed under the old rules; anything filed after faces the new restrictions.
Countries That Allow It Only Under Certain Conditions
Spain
Spain permits dual citizenship selectively. Article 11.3 of the Spanish Constitution authorizes dual nationality treaties with “Ibero-American countries or with those which have had or have special links with Spain.”9Constitute. Spain 1978 (rev. 2011) Constitution Citizens of most Latin American countries, plus Andorra, the Philippines, Equatorial Guinea, and Portugal, can acquire Spanish nationality without giving up their birth citizenship. The constitution also lets Spaniards naturalize in those same countries “without losing their nationality of origin.”
For everyone else, Spanish naturalization requires renouncing the previous citizenship. A Moroccan or Chinese national living in Spain for decades still faces that choice.
South Korea
Article 10 of the Nationality Act sets the default rule: foreign nationals who acquire Korean citizenship must renounce their other nationality within one year.10Ministry of Justice, Republic of Korea. Nationality Act Exceptions exist for people born with multiple nationalities and for individuals who have contributed significantly to the country or possess exceptional ability in science, business, or athletics; these applicants can keep a foreign passport by taking an oath not to exercise it on Korean soil.
The rules are tighter for Korean men born abroad with dual citizenship. Because South Korea has mandatory military service, male dual citizens can only renounce Korean citizenship before March 31 of the year they turn 18. Miss that window and renunciation is generally blocked until military service is completed or until age 38.
Countries That Prohibit Dual Citizenship
Several major countries flatly prohibit it, and acquiring a foreign nationality means automatic loss of the original.
China’s Nationality Law is unambiguous. Article 3 states: “The People’s Republic of China does not recognize dual nationality for any Chinese national.”11National Immigration Administration. Nationality Law of the People’s Republic of China A Chinese citizen who voluntarily acquires another nationality loses Chinese citizenship automatically.
India’s Constitution bars dual citizenship. The Consulate General of India puts it plainly: “Constitution of India does not allow holding Indian citizenship and Citizenship of a foreign country simultaneously.”12Consulate General of India, San Francisco. Notice Regarding Dual Citizenship The Overseas Citizen of India (OCI) card functions as a lifelong visa with additional privileges, but the government is emphatic that it is not citizenship.
Japan prohibits dual citizenship, with courts upholding the ban as recently as 2024. A Japanese citizen who voluntarily acquires a foreign nationality loses Japanese nationality. Singapore, Saudi Arabia, the UAE, Kazakhstan, Nepal, Indonesia, and Malaysia also generally prohibit or heavily restrict dual citizenship. Enforcement and specifics vary, but the underlying rule is the same: one country at a time.
The Tax Trap for American Dual Citizens
Here is where multiple citizenship gets expensive in ways people don’t anticipate. The United States taxes its citizens on worldwide income regardless of where they live or earn.13Internal Revenue Service. U.S. Citizens and Resident Aliens Abroad An American who also holds Canadian or British citizenship and lives abroad still owes the IRS a return every year. Most other countries tax on residency, not citizenship, so the obligation catches people off guard.
The Foreign Earned Income Exclusion softens the impact. For 2026, qualifying Americans abroad can exclude up to $132,900 in foreign earnings, plus up to $39,870 in foreign housing expenses.14Internal Revenue Service. Figuring the Foreign Earned Income Exclusion It covers only earned income; investment returns, pensions, and rental income are not exempt.
Two separate reporting obligations carry the sharpest penalties. If the combined value of your foreign financial accounts exceeds $10,000 at any point in the year, you must file the FBAR (FinCEN Form 114) with the Treasury, separately from your tax return.15Internal Revenue Service. Report of Foreign Bank and Financial Accounts (FBAR) FATCA reporting on Form 8938 kicks in at higher thresholds: for a single filer living abroad, $200,000 in foreign financial assets on the last day of the year or $300,000 at any point during it; married couples filing jointly, $400,000 and $600,000.16Internal Revenue Service. Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets Missing either filing can cost $10,000 or more per violation, and willful noncompliance is worse. Dual citizens sometimes owe more in penalties than they would have owed in tax.
What a Second Passport Won’t Do
A second citizenship does not double your consular protection. Under the 1930 Hague Convention, “A State may not afford diplomatic protection to one of its nationals against a State whose nationality such person also possesses.”17Refworld. Convention on Certain Questions Relating to the Conflict of Nationality Laws If you hold both U.S. and Iranian citizenship and run into legal trouble in Iran, the U.S. embassy may be unable to help.
The same principle applies to military conscription. If one of your citizenships carries mandatory service, being present in that country can trigger the obligation, and your other government has no power to override it. Australia’s government warns dual nationals of exactly this. South Korea’s rules for male dual citizens are the clearest live example.
How U.S. Citizens Can Still Lose Their Citizenship
The U.S. allows dual citizenship, but certain voluntary acts, performed with the specific “intention of relinquishing United States nationality,” can still trigger loss under 8 U.S.C. ยง 1481.18Office of the Law Revision Counsel. 8 USC 1481 – Loss of Nationality by Native-Born or Naturalized Citizen The statutory acts are:
- Naturalizing in a foreign country with intent to give up U.S. citizenship
- Swearing allegiance to a foreign government after age 18 with that same intent
- Serving in a foreign military that is fighting the United States, or serving as an officer in any foreign military
- Working for a foreign government after age 18 in a position that requires an oath of allegiance
- Formally renouncing citizenship before a U.S. consular officer abroad
- Committing treason or attempting to overthrow the U.S. government, if convicted
The State Department applies a presumption that routine acts like naturalizing abroad or taking a foreign oath of allegiance are done with intent to retain U.S. citizenship, not relinquish it.1U.S. Department of State. Dual Nationality In practice, losing U.S. citizenship almost always requires a deliberate, formal renunciation. The statute is still worth knowing about, especially before agreeing to foreign military service.
Applying for a Second Citizenship
Requirements vary by country, but certain documents show up almost everywhere: certified birth certificates for you and the relatives who establish eligibility, marriage certificates, and government-issued photo ID. Ancestry claims usually require original civil records for parents and grandparents going back to the country of origin.
Documents going to a foreign government typically need an apostille, the standardized international authentication stamp. In the U.S., apostilles come from the Secretary of State’s office in whichever state issued the document.19USAGov. Authenticate an Official Document for Use Outside the U.S. Fees run roughly $10 to $26 per document depending on the state. Tracking down decades-old vital records and getting them authenticated can take months.
Processing times vary widely. Ireland’s Foreign Birth Registration runs about 12 months. Italy’s consular applications historically took two to four years, and the 2025 reform will likely add delays as consulates absorb the policy change. Application forms and specific requirements are on the relevant consulate or ministry website, and filing through the wrong office or with incomplete paperwork is the most common cause of delay. Checking the receiving consulate’s exact requirements before assembling documents saves real time.