One of the forms of obtaining Spanish nationality requires the person concerned to have been a legal resident in Spain for an uninterrupted period of ten years immediately prior to the application. In the following cases, the residence period may be shortened:
- Five years: For the concession of Spanish nationality persons who have obtained refugee status.
- Two years: For nationals of Ibero-American countries, Andorra, the Philippines, Equatorial Guinea and Portugal, as well as persons of Sephardic origin.
- One year for:
- Persons born on Spanish territory.
- Persons who did not duly exercise their right to acquire Spanish nationality by option.
- Persons who have been legally subject to guardianship (under the charge of a guardian) or foster care (the kind of foster care that enables reducing the required term of legal residence to one year is that in which there is a resolution by the public body established in each territory to protect minors, and judicially recognized foster care) by a Spanish citizen or institution for two consecutive years, even if this is still the person's situation at the moment of application
- Persons who, at the moment of application, have been married to a Spaniard for a year and are not separated de jure or de facto.
- Widowers or widows of Spaniards, if they were not separated de jure or de facto at the time of the spouse's death.
- Persons born outside Spain to parents (also born outside Spain) and grandparents all of whom were originally Spanish.
- Moreover, the individuals concerned must prove good citizenship and a sufficient degree of integration in Spanish society.