Concept
Whether a person may hold two passports is decided by two laws that do not talk to each other. The law of the country of origin decides whether its citizen who voluntarily takes another nationality keeps the first one. The law of the country of naturalisation decides whether the newcomer must give up the old one to be admitted. Keeping both citizenships requires the origin to permit retention and the destination not to require renunciation — and the destination's tolerance says nothing about the origin's.
The asymmetry is what makes the decision expensive. Germany has let naturalised citizens keep their previous nationality since its 2024 reform, and every Caribbean citizenship-by-investment programme does the same; an applicant from Kazakhstan, China, India or Japan must still apply the origin country's loss rules and exceptions. Loss may occur by operation of law or require a decision, depending on the country and the facts; a foreign grant does not establish one universal date of loss. It can affect property rights, inheritance, residence and the right to return that attach to the first citizenship. The question is therefore asked before the application, not after the oath.
A third layer sits on top of the two laws: what the first state still demands of a citizen who keeps both. Russia and Belarus keep their citizens but require them to report a second citizenship; Singapore and Austria tie renunciation to military service; the United States taxes its citizens wherever they live. None of this is visible in a programme brochure.
The map below covers twenty-four countries chosen for the families that most often face the question — the post-Soviet states, the large Asian origin countries, the European naturalisation routes that demand or waive renunciation, and the citizenship-by-investment jurisdictions. It deals with nationality acquired voluntarily by an adult; dual nationality from birth runs on different rules, set out in citizenship by birth.
The rule in each country
| Country | Position | Own citizen who naturalises abroad | Foreigner naturalising here | Exceptions that matter |
|---|---|---|---|---|
| Russia | allowed; treated only as a Russian citizen (art. 10(1) of Law 138-FZ) | keeps Russian citizenship (art. 10(2)) | no renunciation condition on the general route (art. 15) | — |
| Belarus | not recognised, not lost (art. 11 of Law 136-Z) | keeps Belarusian citizenship | must lose or apply to end the other citizenship (art. 14) | where ending it is impossible for reasons beyond the applicant |
| Kazakhstan | prohibited (art. 3 of the Citizenship Law) | loses citizenship (art. 21(5)) | refused while holding another citizenship (art. 17(7)) | ratified treaties; a notarised renunciation request for listed categories |
| Uzbekistan | not recognised (art. 12 of Law ZRU-610) | loses on voluntary acquisition (art. 25(d)), by decision of the President | must have left the foreign citizenship (art. 19(a)) | — |
| Azerbaijan | foreign citizenship is generally not recognised in Azerbaijan (art. 10) | voluntary acquisition is a ground for loss; a court decides under art. 18, subject to the art. 17 limitations | art. 14 and the published naturalisation checklist contain no general requirement to renounce existing citizenship; this is not recognition of that foreign citizenship after admission | art. 10 exceptions: international treaties and cases resolved under art. 109(32) of the Constitution; retention of the prior nationality also depends on its own law |
| Ukraine | multiple citizenship recognised in listed cases from 16 January 2026 (Law 4502-IX) | loses by presidential decree on acquiring the aggressor state's citizenship or that of a state outside the list | simplified route keeps a listed citizenship | 33 listed states: the EU states, the UK, the US, Canada, Norway, Iceland, Switzerland |
| China | not recognised (art. 3 of the Nationality Law) | loses automatically once settled abroad and naturalised (art. 9) | may not retain foreign nationality (art. 8) | — |
| India | not permitted | citizenship terminates; a foreign passport is conclusive proof (s. 9 of the Citizenship Act) | — | the OCI card, which is not citizenship |
| Japan | not permitted for adults | loses automatically on acquiring a nationality by choice (art. 11) | must lose the previous nationality as a rule (art. 5) | dual nationals from birth choose by age 20 |
| Singapore | not permitted | deprivation on acquiring foreign citizenship (art. 134 of the Constitution) | oath of renunciation | male citizens' renunciation withheld until National Service is discharged |
| Germany | allowed since the 2024 reform (§ 25 StAG repealed) | keeps German citizenship | no renunciation condition (§ 10) | — |
| Netherlands | not allowed as a rule | loses automatically, wherever living | must renounce | statutory exceptions in both directions |
| Austria | restricted | loses unless retention was approved in advance (§ 27 StbG) | must take the steps to leave the previous nationality (§ 10(3)) | grant in the special interest of the Republic (§ 10(6)) |
| Spain | restricted | loses after 3 years abroad unless declaring the wish to keep it (art. 24 CC) | declaration renouncing the former nationality (art. 23(b)) | Ibero-American countries, Andorra, the Philippines, Equatorial Guinea, Portugal, Sephardic origin |
| Latvia | only with listed states (s. 9) | keeps with EU, EFTA, NATO states, Australia, Brazil, New Zealand, treaty states | renunciation, except citizens of the same list (s. 12) | Cabinet authorisation in important state interests |
| Estonia | not allowed (§ 1(2) of the Citizenship Act) | ceases to be a citizen on accepting another citizenship (§§ 22, 29) | must prove release from the previous citizenship (§ 12(2)) | international protection where renunciation is impossible (§ 3(2)); a minor with two citizenships chooses within 3 years after turning 18 (§ 3(1)) |
| Lithuania | only in the listed cases (art. 7, current consolidated Law XI-1196) | loss from acquisition unless an applicable statutory exception applies (art. 26) | ordinary naturalisation generally requires loss of the prior citizenship: art. 18(1)(6), art. 40(5) undertaking and art. 23 proof rules; refugees are exempt under art. 18(5) | includes qualifying pre-11 March 1990 exiles/emigrants and descendants, citizenship acquired automatically through marriage, and Lithuanian citizenship at birth plus another citizenship at birth or before 18; the last case continues into adulthood, with no age-21 choice requirement (MFA guidance) |
| Serbia | allowed for its citizens | keeps Serbian citizenship | release from the foreign citizenship or proof it will follow (art. 14) | admission in the interest of Serbia (art. 19); spouses and emigrants without release |
| Montenegro | restricted | loses by law on voluntary acquisition (art. 24) | release from the other citizenship (art. 8) | special-interest admission (art. 12); treaties on reciprocity (art. 18) |
| Türkiye | allowed (art. 44 of Law 5901) | keeps; leaving requires permission (art. 25) | no renunciation condition (arts. 11–12) | investor route under art. 12 |
| Portugal | allowed | keeps Portuguese citizenship; loss only on a declaration by a person who holds another nationality (art. 8 of Law 37/81) | previous citizenship kept; no renunciation among the conditions of art. 6 | — |
| Cyprus | dual nationality recognised (HM Passport Office guidance, July 2026) | another nationality is compatible with Cypriot citizenship | Cyprus permits retention of another nationality; whether it survives also depends on the origin country's law | the published M127 naturalisation procedure sets the admission conditions; dual-nationality permission does not guarantee admission |
| Caribbean five (CBI) | allowed: Antigua and Barbuda, Dominica, Grenada, St Kitts and Nevis, Saint Lucia | multiple nationality is permitted; the nationality rules of the other country still apply | the programmes permit holding another citizenship; its retention remains subject to the origin country's law | processing of Russian and Belarusian applications suspended under the six CBI principles agreed by the heads of government in February 2023 |
| United States | allowed | keeps US citizenship | — | — |
What follows in practice
The second table keeps only the countries where holding or acquiring a second citizenship triggers a duty, a service link or a tax consequence.
| Country | Duty to report | Military and state-service link | Tax link | What triggers loss or a sanction |
|---|---|---|---|---|
| Russia | MVD within 60 days, for citizenship and for a foreign residence permit (art. 11 of 138-FZ) | all duties of a Russian citizen apply | none; tax follows residence | late filing RUB 500–1,000; failure to notify up to RUB 200,000 under art. 330.2 of the Criminal Code |
| Belarus | within 3 months, for citizenship and for residence documents (art. 11) | duties of a Belarusian citizen cannot be evaded | none | loss on foreign state or military service (art. 19) |
| Kazakhstan | within 30 days, with surrender of the passport and ID (art. 21) | loss on foreign military or state service | none | liability for not reporting; loss also for using foreign documents after acquiring Kazakh citizenship (from 28 May 2024) |
| Uzbekistan | — | duties continue until the President's decision (art. 12) | none | loss after 7 years abroad without consular registration (art. 25(b)) |
| Azerbaijan | written notification within one month under art. 10 | voluntary service in foreign state or municipal bodies or armed forces is a ground for loss; a court decides (art. 18) | none | the former criminal offence for failure to notify (Criminal Code art. 318-2) was repealed in 2020; the notification duty remains |
| Ukraine | — | loss on contract service for the aggressor state (art. 19) | none | loss dated by the presidential decree |
| India | surrender of Indian documents | — | none | automatic termination; the foreign passport is the proof |
| Japan | choice of nationality for dual nationals from birth | — | none | automatic loss; the Minister may demand a choice |
| Singapore | — | National Service for male citizens and PRs | none | NS default: fine up to S$10,000 or up to 3 years |
| Austria | — | men aged 16–36 who have not served cannot renounce (§ 37); foreign military service leads to deprivation (§ 32) | none | automatic loss without prior retention |
| Latvia | — | voluntary service in armed forces outside the listed states leads to revocation (s. 24) | none | revocation where another citizenship was acquired without renouncing |
| Lithuania | within 2 months, to the authorised institution or a consulate (art. 26(2)) | loss on service of another state without Government authorisation (art. 24) | none | loss dated from the acquisition itself |
| Montenegro | — | unsettled military obligation elsewhere replaced by a written undertaking (art. 8) | none | loss by law |
| Türkiye | registration of the second citizenship (art. 44) | permission to leave refused to persons wanted for military service (art. 25) | none | — |
| United States | — | — | worldwide income wherever living; exit tax on renunciation for covered expatriates | renunciation fee USD 450 from 13 April 2026, down from USD 2,350 (final rule 2026-04931) |
What the two tables show
The map has three broad groups, subject to the exceptions in each row. The first generally permits its citizens to hold another nationality: Russia, Belarus, Germany, Serbia, Türkiye, Portugal, Cyprus, the Caribbean states and the United States. The second has loss rules or restrictions when another nationality is acquired by choice: Kazakhstan, Uzbekistan, Azerbaijan, China, India, Japan, Singapore, Estonia, the Netherlands, Austria without prior permission, and Montenegro. The third sits in between and turns on a list or a formality — Ukraine's 33 states, Latvia's EU, EFTA and NATO list, Lithuania's statutory cases for pre-1990 exiles and their descendants, Spain's three-year declaration and its Ibero-American exception. The decision-maker and effective date of loss must be checked separately; in Azerbaijan, art. 18 requires a court decision.
The second group is the one where the decision is irreversible, and it is also where the audience of this map is largest. For a citizen of Kazakhstan or Uzbekistan an EU naturalisation, a Turkish investor passport or a Caribbean citizenship all count as voluntary acquisition, and none of the origin laws carves out an exception for investment or for a passport held "in reserve". Kazakhstan closed the reserve strategy explicitly: since 28 May 2024 using the documents of another citizenship after acquiring Kazakh citizenship is itself a ground of loss, and the 30-day reporting duty comes with the surrender of the Kazakh passport.
Destination rules decide less than they seem to. A generous destination does not help a citizen whose origin state removes citizenship on acquisition; a strict destination — the Netherlands, Austria, Latvia outside its list, Montenegro, Serbia on the general route — asks the newcomer to give up a citizenship that the origin state may not even allow them to give up. Several of these states have a way out for exactly that case: Serbia and Montenegro accept a written statement where release is impossible, Belarus waives the condition where ending the other citizenship is beyond the applicant's control, and Japan admits a person whose nationality cannot be lost regardless of their will.
The obligations of the third layer are cheaper to meet than to breach. Russia's 60-day notice, Belarus's three months and Kazakhstan's 30 days are simple filings; breaching them turns a lawful status into an offence, and in Russia outright failure is a criminal one. Military service is the less visible trap: Singapore withholds renunciation until National Service is done, Austria bars renunciation for men who have not served, and Türkiye refuses permission to leave to anyone wanted for service.
Profile against strategy
| Profile | Strategy | Why |
|---|---|---|
| Citizen of Kazakhstan or Uzbekistan who wants mobility | a residence permit — in the EU, the UAE or Türkiye — rather than a second passport; naturalise only when the first citizenship is no longer needed | any voluntary acquisition ends the first citizenship; Kazakh property, inheritance and residence then run on foreigner rules |
| Citizen of a state that keeps its nationals — Belarus, Serbia, Türkiye and others in the first group | a destination without a renunciation rule — Germany, Portugal, Cyprus, Italy, France — plus the home reporting duty | the origin law is not the constraint; the destination's renunciation rule and any home notice are |
| Ukrainian citizen | naturalisation in one of the 33 listed states | outside the list — Türkiye, the Gulf, the Caribbean — voluntary acquisition is a ground of loss |
| Citizen of China, India, Japan or Singapore | long-term residence without naturalisation; India's OCI after renunciation | risk of losing the first citizenship, subject to the origin country's conditions and exceptions |
| Family that must keep the origin passport and wants an EU one | Germany, Portugal, Cyprus, Italy or France; avoid the Netherlands, Austria, Estonia, Latvia and Lithuania outside their lists and, outside its exceptions, Spain | the destination's renunciation rule becomes the binding constraint |
| Parents of a child who is a dual national from birth | check the origin's choice rules before the child's majority | Japan requires a choice by age 20; Uzbekistan removes citizenship at 21 unless the foreign one is left |
| US citizen | a second passport changes mobility, not tax | citizenship-based taxation follows the US passport; leaving it costs USD 450 and, for covered expatriates, an exit tax |
Citizenship by investment: the trap in the application form
An investment citizenship is sought voluntarily, so the origin country’s rules on voluntary acquisition must be checked. The Caribbean five, Türkiye, Egypt, Jordan or Vanuatu make no difference here: for countries with restrictive origin rules, the grant may trigger loss of the first citizenship under that country's conditions and procedure, and the programme's own tolerance of dual nationality protects only the second passport. The comparison of the programmes themselves is in citizenship by investment; what they are worth as a portfolio is in second passport as Plan B.
The practical risk surfaces at the border, at a consulate or at a passport renewal rather than on the day of the grant, which is why "nobody will know" is the most expensive assumption on the map. India treats the foreign passport itself as conclusive proof; Kazakhstan attaches loss to the mere use of foreign documents; the Netherlands and Japan apply loss without any procedure at all. Revocation risk runs in the other direction too: purchased passports have been cancelled for misrepresentation, and a citizen who has already lost the first nationality and then loses the second is left facing statelessness.
Typical mistakes
- Reading the destination's rule as the answer. A Caribbean or German "yes" to dual citizenship says nothing about the country being left.
- Treating an investment passport as a reserve. Strict origin laws make no exception for it, and Kazakhstan now penalises the use of foreign documents as such.
- Missing the reporting clock. Russia's 60 days also cover a foreign residence permit, Belarus's three months also cover residence documents, Kazakhstan's 30 days come with surrender of the passport.
- Forgetting military service. Singapore, Austria and Türkiye link the right to leave or renounce to service already done.
- Relying on the Spanish formality. The renunciation declaration of article 23 is required outside the Ibero-American group, and a Spaniard abroad loses Spanish nationality after three years without a declaration to keep it.
- Ignoring children. Japan's choice at 20 and Uzbekistan's rule at 21 catch dual nationals from birth who never applied for anything.
Q/A
Does buying a Caribbean or Turkish passport cost a Kazakh citizen their citizenship?
Yes. Kazakhstan does not recognise another citizenship for its citizens and treats its acquisition as a ground of loss under article 21(5) of the Citizenship Law; the law makes no exception for investment programmes. The person must report within 30 days and surrender the Kazakh passport and ID, and since 28 May 2024 using foreign documents after acquiring Kazakh citizenship is a separate ground of loss.
Which origin countries keep their citizens after a naturalisation abroad?
On this map: Russia, Belarus, Germany since its 2024 reform, Serbia, Türkiye, Portugal, Cyprus, the Caribbean states and the United States. Several of them attach a duty to the second citizenship rather than a loss — Russia a notice within 60 days under article 11 of Law 138-FZ, Belarus within three months, Türkiye a registration of the second citizenship — and both Russia and Belarus treat such a person on their territory only as their own citizen.
Which EU countries still make a newcomer renounce?
Among the countries on this map: the Netherlands as a rule, Austria (subject to the special-interest grant), Estonia, which asks for proof of release from the previous citizenship (§ 12(2) of the Citizenship Act), Lithuania, whose ordinary route generally requires loss of the previous citizenship, with an undertaking and proof under arts. 18, 23 and 40 of Law XI-1196 and the refugee exception in art. 18(5), Latvia outside its list of EU, EFTA and NATO states, Australia, Brazil and New Zealand, and Spain outside the Ibero-American group, where a declaration of renunciation is formally required. The full naturalisation picture for fourteen member states is in EU citizenship routes, and the ladder from permit to passport, with the absence rules that break it, in the lifecycle of a migration status.
What changed for Ukrainians in 2026?
From 16 January 2026 Law 4502-IX recognises multiple citizenship in listed cases. A Ukrainian adult who voluntarily acquires the citizenship of one of the 33 states on the Cabinet's list — the EU states, the United Kingdom, the United States, Canada, Norway, Iceland and Switzerland — no longer loses Ukrainian citizenship on that ground; acquiring the aggressor state's citizenship or that of a state outside the list remains a ground of loss by presidential decree.
Does a second citizenship change where tax is paid?
Almost nowhere on this map. Tax follows residence in every country here except the United States, which taxes its citizens on worldwide income wherever they live; a second passport neither creates nor ends tax residence. The tax consequence of citizenship arises on leaving the American one: an exit tax for covered expatriates, set out in renunciation of citizenship.
What happens if the destination demands renunciation but the origin country does not allow it?
Several destinations provide for that case. Serbia accepts a written statement renouncing the foreign citizenship where release is not possible, Montenegro accepts an undertaking where release was refused over military obligations, Belarus waives the condition where ending the other citizenship is beyond the applicant's control, and Japan admits applicants whose nationality cannot be lost regardless of their will.