Each country determines the laws through which citizenship can be acquired or granted, based on various criteria. The most common ways to attain dual citizenship are through:
- Birth
Being born in country that grants citizenship by birth or to parents who are citizens of a country that grants citizenship by descent. In some countries, even if a certain individual is a non-resident, citizenship may still granted provided that the applicant’s parents were born in the country.
- Naturalisation
Naturalisation is the process whereby citizenship is granted to a foreign resident of a country, normally if a minimum number of years are met in which the person has resided in the country. The process requires an applicant to first have achieved permanent residency status. Irish law, for instance, dictates that a foreign person may become an Irish citizen if five years of reckonable residence are satisfied within a nine-year period.
- Marriage
Marrying a citizen of a foreign country generally grants an individual the ability to obtain residency within the country. However, several countries do offer expedited naturalisation to foreigners who marry citizens of their country. For instance, foreigners married to a Spanish citizen are able to apply for Spanish citizenship after only a year of tax residency in the country.
- Adoption
Foreign-born adopted children may, under conditions specific to different country legislations, automatically be granted citizenship provided that at least one adoptive parent is a citizen either by birth or through naturalisation.
- Citizenship by Investment Programmes
Citizenship by Investment programmes allow investors to acquire a second citizenship through investments made in a foreign country.
People holding dual citizenship can exercise the rights conferred to them at law in the countries in which they hold citizenship. Persons attaining dual citizenship would in general be required to show a genuine link with the country issuing the citizenship.