If Swiss citizenship is lost
- through forfeiture: i.e. because they were born abroad, and the birth was neither reported to a Swiss representation within the prescribed period nor registered in the Swiss civil register (see FAQ of the SEM, available in German, French or Italian only), or
- through relief of citizenship: i.e. at their request, any Swiss citizen may be relieved of their Swiss citizenship, or
- by marriage of a Swiss woman to a foreign national before 1 January 1992 (unless a declaration of retention of Swiss nationality has been signed),
it is possible, in accordance with Article 27 of the Swiss Citizenship Act (SCA), to apply for reinstatement of Swiss citizenship within ten years from the time of loss of nationality. Once this period has expired, reinstatement is only possible after three years of residence in Switzerland.