Jus sanguinis

1. All people residing in Iran except those whose foreign nationality is established; the foreign nationality of such people is considered to be established if their documents of nationality have not been objected to by the Iranian Government.
2. Those born in Iran or outside whose fathers are Iranian.
3. Those born in Iran of unknown parentage.
4. People born in Iran of foreign parents, one of whom was also born in Iran.
5. People born in Iran of a father of foreign nationality who have resided at least one more year in Iran immediately after reaching the full age of 18; in other cases their naturalization as Iranian subjects will be subject to the stipulations for Iranian naturalization laid down by the law.
6. Every woman of foreign nationality who marries an Iranian husband.
7. Every foreign national who has obtained Iranian nationality.

However, this is not the case for children born abroad if any of their German parents were born abroad after 31 December 1999 and do not have their primary residence in Germany: the child is not automatically a German citizen by birth, but can acquire German citizenship as long as any of their German parents register their birth with the responsible German diplomatic mission within one year of the child's birth. This limitation does not apply if the child would otherwise be stateless or if one foreign-born German parent was born on or before 31 December 1999. Thus, the German citizenship of future generations born abroad can be preserved by having each child's birth registered with the German diplomatic mission within one year of birth.

Furthermore, Article 116(1) of the German Basic Law confers, within the confines of the laws regulating the details, a right to citizenship upon any person who is admitted to Germany (in its borders of 1937) as "refugee or expellee of German ethnic origin or as the spouse or descendant of such a person." At one time, ethnic Germans living abroad in a country in the former Eastern Bloc (Aussiedler) could obtain citizenship through a virtually automatic procedure.^[30] Since 1990 the law has been steadily tightened to limit the number of immigrants each year.^{[citation needed]} It now requires immigrants to prove language skills and cultural affiliation.

Article 116(2) entitles persons (and their descendants) who were denaturalised by the Nazi government, to be renaturalised if they wish. Those among them who took their residence in Germany after 8 May 1945, are automatically to be considered German.

Both paragraphs (1) and (2) result in a considerable number of Poles and Israelis, residing in Poland and Israel respectively, being concurrently German.

In addition, the "Status Law" of 2001 grants certain privileges to ethnic Hungarians living in territories that were once part of the Austro-Hungarian Empire. It permits them to obtain an identification card but does not confer the right to full Hungarian citizenship. According to the latest Citizenship Law adopted in 2010, anybody, possessing certain evidence (certificates, documents) of his or her Hungarian roots from around the World can apply for Hungarian citizenship. The interview is led in Hungarian either in Hungary or at one of the Consulates abroad.

See also Irish nationality law and twenty-seventh Amendment of the Constitution of Ireland.

In 1967–1968 the Communist State issued to Jews emigrating from Poland to Israel, instead of passports, a so-called travel document which granted them the right to exit Poland but not of re-entering it, in effect taking away their Polish citizenship on the assumption that, in emigrating or traveling to Israel, they renounced it themselves. In a 2005 verdict, the Supreme Administrative Court of Poland ruled that this action was illegal based on the state of law at that time. Consequently, it is now assumed the Jews who emigrated after 1968 have remained Polish citizens and their citizenship will be certified on request.^[32]

Persons with at least one Slovak grandparent and "Slovak cultural and language awareness" may apply for an expatriate identity card entitling them to live, work, study and own land in Slovakia. Expatriate status is not full citizenship and does not entitle the holder to vote, but a holder who moves his or her domicile to Slovakia may obtain citizenship under preferential terms.

Due to Switzerland's high immigrant population, there are more than a million people who were born and have spent their entire lives in Switzerland but are not Swiss citizens due to their parents being immigrants. Some Swiss-born third-generation immigrants even have Swiss-born parents but are not Swiss citizens if neither of their parents have naturalised. To obtain Swiss citizenship, people in this position must undergo naturalisation proceedings, which have a high bar to satisfy the "integration" criterion. The unusual rules hit international headlines in 2017 when a woman born in Switzerland to Turkish parents, who is a native Swiss-German speaker and has spent her entire life in Switzerland, had her citizenship application denied by the local municipality on "integration" grounds as she could not name enough Swiss mountains, cheeses and retail brands, and was deemed not to have gone skiing often enough.^[33] The decision was overruled by the cantonal government several months later.^[34]

In 2017, Swiss voters in a nationwide referendum agreed to relax the citizenship criteria for third-generation immigrants slightly: although they will still not be Swiss citizens at birth and will need to apply for citizenship, they will no longer have to take naturalisation tests or interviews if their parents and grandparents are long-time permanent residents.^[35][36]

This approach has been a tradition since the new constitutional foundation of Bulgaria in 1879, following the liberation from Ottoman yoke in 1878, when large numbers of ethnic Bulgarians remained outside of the state borders. Bulgaria and Greece were subject to a population exchange following the Second Balkan War. The conditions of the treaty settlement mandated that they accept individuals claiming respective ethnic origin.

In addition, ethnic Greeks who join the armed forces acquire automatic citizenship by operation of Article 10, with the military oath taking the place of the citizenship oath. This position arises from the fact that approximately 85% of known ethnic Greeks were outside the boundaries when the country was formed, and 40% remained outside the final boundaries at the beginning of World War I. Most were de jure stripped of their host country citizenship with the outbreak of war if the host country was at war with Greece. In the late 19th century, Greece had a wider diaspora because of poverty and limited opportunities.

While those with sufficient Jewish ancestry to qualify for the Law of Return who grew up with a religion other than Judaism and secular Jews are eligible to immigrate to Israel, Jews who voluntarily convert to another religion are not. Converts to Judaism who wish to immigrate to Israel are evaluated on a case-by-case basis by the Israeli Interior Ministry, which determines whether the conversion was sincere in its view.^[40]

Israeli law also recognizes the descendants of Israeli emigrants living abroad as Israelis; this applies only to the first generation born abroad. Non-Jews can become naturalized after five years of residency and acquisition of a basic knowledge of Hebrew.

Minor children of Italian citizens were at risk of losing Italian citizenship if the child's parent naturalized in another country, unless the child was subject to an exception to this risk—and children born and residing in a country where they held dual citizenship by jus soli were subject to such an exception since 1 July 1912. Until 1 January 1948, Italian law did not generally permit women to pass on citizenship. Persons born before that date are in most cases not Italian citizens jus sanguinis if their line of descent from an Italian citizen depends on a female at some point before 1948. On several occasions, this limitation of deriving Italian citizenship only from fathers before 1948 has been successfully challenged in court.

Every person of I-Kiribati descent […] shall […] become or have and continue to have thereafter the right to become a citizen of Kiribati […]. Every person of I-Kiribati descent who does not become a citizen of Kiribati on Independence Day […] shall, at any time thereafter, be entitled upon making application in such manner as may be prescribed to be registered as a citizen of Kiribati.

Nationals such as the Kachin, Kayah, Karen, Chin, Burman, Mon, Rakhine or Shan and ethnic groups as have settled in any of the territories included within the State as their permanent home from a period anterior to 1185 B.E., 1823 A.D. are Burma citizens.^[43]

The Jewish Law of Return allows descendants of Portuguese Jews who were expelled in the Portuguese Inquisition to become citizens if they 'belong to a Sephardic community of Portuguese origin with ties to Portugal'.

Under the Constitution of South Korea, North Korea is part of the Republic of Korea. Therefore, North Korean citizens are also recognized as South Korean nationals. All North Koreans of good conduct are granted citizenship upon arrival to South Korea.

Turkey and Greece reciprocally expelled their minorities in the early 1920s after World War I. They were mandated by international treaty to accept incoming populations as citizens based on ethnic background.