The Andorran law is strictly pursuant to the ius sanguinis principle. In this sense, there are different ways of acquiring nationality: by full adoption, by the Andorran nationality of a parent or grandfather, by marriage, by naturalisation, or by naturalisation of one of the parents.
On the other hand, in the case of Andorran nationality of origin, the regulations establish that the child is Andorran when he/she fulfils one of the following conditions: the child is born in Andorra to an Andorran father or mother; the child is born abroad to an Andorran father or mother born in Andorra; an underage child is adopted by an Andorran person or a foreigner and resident in Andorra; the child is born in Andorra of father or mother born in Andorra, resident and without Andorran nationality; the child is born in Andorra of foreign parents and residents in Andorra and at least one of the parents must be a resident for at least 10 years after the baby is born; and finally, if the child was born abroad accidentally, proving that, besides fulfilling the requirements described above, he/she also has the right to nationality if the mother is a resident. The application must be submitted during the first year of the baby’s life.
The acquisition of Andorran nationality is a long process and implies the express waiver of the current nationality/ies of the applicant, as dual citizenship is strictly forbidden. In addition, an examination of the Catalan language, history, and geography of Andorra is mandatory for adults. As soon as the person meets the requirements, the application for citizenship is presented and a provisional passport is granted. From this moment the applicant has 5 years to pass the exam and present the documents of renunciation to his current nationality in order to obtain Andorran nationality and a definitive passport. In all cases to apply for citizenship, it is essential to be a legal and effective resident in Andorra at the time of filing the application.