Quick summary: Most popular destinations allow dual citizenship: the USA, Canada, UK, Australia, New Zealand, France, Germany (as of 06/2024), Portugal, Greece, Turkey, and five Caribbean nations. Countries requiring renunciation include Singapore, Japan, China, India, Indonesia, Malaysia, Austria, and conditionally the Netherlands, Spain, and South Korea. For most people, the new country's law—not your original country's—is the real barrier.
There's a striking paradox when you compare citizenship law against passport rankings: some of the world's strongest passports are the hardest to hold alongside another. According to QuocTich.com data updated 09/2026, nearly half of the top 17 passports on the global ranking belong to countries that ban or restrict dual citizenship for naturalized citizens.
This means if you want to hold a top-tier passport like Singapore's or Japan's, you'll likely have to renounce your original citizenship. In countries permitting dual citizenship, the price is instead years of residency or investment capital. This guide ranks countries across both axes: dual citizenship policy and passport strength.
This article summarizes legal frameworks to help you plan ahead—it does not replace legal counsel for your specific situation. Citizenship laws change; verify current regulations before making decisions.
Two sides of the equation: the new country must allow it, and your original country must not forbid it
Dual citizenship only exists when both countries allow you to hold the other's citizenship. Most people ask only one question, then discover the other problem after submitting their application.
The first direction is your original country's law. Under most citizenship laws, acquiring citizenship in another country does not automatically strip your original citizenship. You only lose it by formally requesting renunciation and having it approved, being stripped for cause, or falling into narrow circumstances in law. Vietnam, for instance, does not treat naturalization abroad as automatic grounds for loss. The second direction is the new country's law—and this is where you often hit a wall. If a country requires proof that you have renounced your original citizenship, you must obtain an official decision from your original country before you can be sworn in as a citizen of the new country.
Dual citizenship permitted: most familiar destinations
The table below includes countries that expats commonly consider and that permit citizens to hold another citizenship upon naturalization. The passport strength column shows how many countries grant visa-free or visa-on-arrival entry, using QuocTich.com data updated 09/2026.
| Country | Dual citizenship policy for naturalized citizens | Visa-free destinations | Ranking |
|---|---|---|---|
| Germany | Permitted as of 27/06/2024 | 165 | 3 |
| France, Italy | Permitted | 165 | 3 |
| Sweden, Norway, Denmark, Finland | Permitted (Denmark since 2015, Norway since 2020) | 165 | 3 |
| Ireland, Switzerland, Luxembourg | Permitted | 164 | 4 |
| Portugal, Belgium | Permitted | 163 | 5 |
| UK, Greece, New Zealand | Permitted | 162 | 6 |
| Australia, Canada, Malta | Permitted | 161 | 7 |
| USA | Permitted, though oath includes language renouncing allegiance | 159 | 9 |
| Cyprus | Permitted | 158 | 10 |
| Grenada | Permitted | 146 (published) | 15 |
| St. Kitts & Nevis, Antigua, St. Lucia, Dominica | Permitted | 122–136 | 20–29 |
| Turkey | Permitted, with notification requirement | 115 | 35 |
| Vanuatu | Permitted | 83 | 48 |
Find individual passport rankings and detailed entry policies on the passport index page.
One detail many don't know about the USA: the naturalization oath includes language renouncing allegiance to your original country, but the US does not require you to formally renounce citizenship. Whether that oath language actually severs your original citizenship depends entirely on your original country's law. For most countries, including Vietnam, the answer is no—it does not automatically strip citizenship.
Germany represents the biggest recent change. Before 27/06/2024, non-EU nationals naturalizing in Germany were generally required to renounce their original citizenship. The new law eliminates this requirement, so many families already settled in Germany with five years' residence are now filing applications.
Countries requiring renunciation or allowing dual citizenship only conditionally
| Country | Naturalization policy | Visa-free destinations | Ranking |
|---|---|---|---|
| UAE | No, except in rare exceptional cases | 168 | 1 |
| South Korea | Must renounce, except specific categories (marriage, talent, ethnic Koreans 65+) with commitment not to use foreign citizenship within Korea | 166 | 2 |
| Spain | Must renounce, except citizens of Ibero-American nations, Portugal, Philippines, Andorra, Equatorial Guinea, France | 166 | 2 |
| Singapore | Must renounce | 165 | 3 |
| Netherlands, Austria | Must renounce, with narrow exceptions | 164 | 4 |
| Japan | Must renounce; those born with dual citizenship must choose by statutory deadline | 164 | 4 |
| Malaysia | Does not recognize dual citizenship | 159 | 9 |
| China | Does not recognize dual citizenship | 83 | 48 |
| Indonesia | Does not recognize dual citizenship for adults; limited dual citizenship for children | 80 | 51 |
| India | Does not recognize dual citizenship; offers OCI card as alternative for people of Indian origin | 58 | 68 |
Data from QuocTich.com, updated 09/2026 for both columns. Look at Japan and Singapore and you see the paradox immediately: passports ranked near the top globally, yet acquiring them means renouncing your original citizenship.
Formal renunciation of original citizenship: a step many people forget to budget time for
When a new country requires proof that you have renounced your original citizenship, you need an official decision from your original country's head of state or equivalent authority. This is not a week-long process.
The typical sequence:
- File your renunciation application at your country's diplomatic mission in your current country of residence, or at the relevant domestic authority if you still live at home.
- Prove you have no outstanding tax liability, are not under criminal investigation, and have no unmet legal obligations to the state.
- Your application goes through the Foreign Ministry (or equivalent) to the head of state; this stage typically takes months.
- Receive the official decision, then translate and authenticate it according to the requirements of the country you're naturalizing in.
- Submit the proof of renunciation to the immigration authority to complete the naturalization oath ceremony.
It is not uncommon for naturalization applications in Singapore or Japan to be on hold for many months simply waiting for step three. If you're on this path, start the renunciation process as soon as you're certain you meet naturalization requirements—do not wait until you receive an invitation to take the oath.
Once you renounce, regaining your original citizenship is a separate, much harder process. Assets registered in your original country, especially real estate, may have to be transferred under foreign-ownership rules.
Dual citizenship on paper versus dual citizenship when traveling
Holding two nationalities does not mean two passports are interchangeable.
- Within your country of origin, you are a citizen of that country. Entry and exit use your original passport; if you face legal trouble at home, the other country's government usually cannot intervene diplomatically.
- Airline tickets must match the passport you present at check-in. We've detailed the order in which to use each passport at different borders in a separate article.
- Some countries require notification. Turkey requires citizens to report when they acquire another nationality; South Korea requires dual nationals in specific categories to pledge not to exercise foreign citizenship on South Korean soil.
Downsides of dual citizenship that few mention beforehand
Obligations follow citizenship, not residence. Several countries have military service obligations for male citizens. Families with sons should ask carefully before adding a child to the naturalization application for such a country.
Taxes follow citizenship, not residence. The USA taxes citizens on worldwide income regardless of where they live and requires reporting of foreign financial accounts. This is the biggest difference between a US passport and most others. We do not provide tax advice; you need a tax professional for your specific situation.
Laws change. Germany shifted from banning dual citizenship to permitting it in 2024; the reverse can happen elsewhere. Decisions based on current law should come with a contingency plan.
Children born abroad may acquire dual citizenship without your explicit choice. Then as adults, one country's law may force them to choose, as in Japan or Singapore. Register your child's birth and citizenship intentionally.
Documents from both countries must align. Mismatched names, birth dates, or diacritics across two passports causes years of friction at airports and banks.
Checklist before choosing your naturalization country
- [ ] Does the new country require proof of renunciation of your original citizenship? Are there exceptions that fit your family?
- [ ] If you must formally renounce, how do you handle property and documents in your original country?
- [ ] Does the new country impose military service, worldwide tax, or citizenship disclosure requirements?
- [ ] Will children in your application be forced to choose a single citizenship when they reach adulthood?
- [ ] How many years of residency are required before naturalization? Compare timelines in our residency duration guide.
- [ ] If citizenship is through investment, does the program explicitly protect your right to dual citizenship, as the Grenada program does?
Next steps
Pick two or three countries you're considering, place them on the two tables in this guide, and identify which group each falls into. If any country requires renunciation of original citizenship, calculate the true cost of formal renunciation immediately—not just the cost of a new passport.
Then ask an immigration advisor or attorney one specific question: "If I naturalize in this country, which document proves I retain my original citizenship, and who issues it?" Someone who answers that question clearly is someone who has actually handled this type of file.
