The option is a benefit that Spanish legislation offers to foreign nationals that find themselves in determined conditions, allowing them to acquire Spanish nationality. The following persons are entitled to acquire Spanish nationality by Option:

- Persons who are or have been subject to the parental authority of a Spaniard.

- Persons whose father or mother was Spanish and was born in Spain.

- Persons whose birth in Spain or parentage was not determined (determination of parentage means establishing who a person's parents are) until after they were eighteen years old. In this case, the deadline for opting for Spanish nationality is two years after the parentage or birth has been determined.

- Persons whose adoption by Spaniards took place after the age of eighteen. In this case, the option right will exist for two years following formalisation of the adoption.