Child born to one Icelandic parent and one foreign parent
If a child is born to one Icelandic parent and one foreign parent, the law in force at the time of the child's birth determines whether the child has or had the right to Icelandic citizenship from birth. It is important to know when the child was born, whether the father or mother is an Icelandic citizen, the marital status of the parents and what that status was at the time of the child's birth, as well as whether the child was born in Iceland or abroad.
 
Children born after July 1, 2018
A child born after July 1, 2018, automatically acquires Icelandic citizenship at birth if one of the parents is an Icelandic citizen. The Icelandic National Registry is responsible for registering children who automatically acquire Icelandic citizenship; please consult the National Registry's instructions.
​
Child of a parent who became an Icelandic citizen after their birth
A person whose parent became an Icelandic citizen after their birth may apply for Icelandic citizenship through a general request. The condition is that the person has legally resided in Iceland for the past two years and that the parent has been an Icelandic citizen for at least five years.

Icelandic citizens born abroad
It is important to keep in mind that Icelandic citizens born abroad who have never had legal residence in Iceland, or who have never lived or stayed in the country, may lose their citizenship at age 22. You can request confirmation of the maintenance of Icelandic citizenship by sending a request to the Immigration Office.