This thread will focus more on the Constitution, the Citizen of Zimbabwe Act is yet to be aligned with the constitution.
There are three types of citizenship, that is:
Citizenship by Birth
Citizenship by Descent
Citizenship by Registration
Citizenship By Birth (Section 36)
You are a citizen by birth if:
(1) You were born in Zimbabwe and, Either your mother or their father was a Zimbabwean citizen; or Any of your grandparents was a Zimbabwean citizen by birth or descent.
(2) If you were born outside Zimbabwe you are Zimbabwean citizen by birth if, when you were born, either of your parents was a Zimbabwean citizen and—
(a) Ordinarily resident in Zimbabwe; or
(b) Working outside Zimbabwe for the State or an international organisation.
(3) A child found in Zimbabwe who is, or appears to be, less than fifteen years of age, and whose nationality and parents are not known, is presumed to be a Zimbabwean citizen by birth.
Citizenship By Descent (Section 37)
This is when:
(a) Either of your parents or any of your grandparents was a citizen by birth or descent; or
(b) Either of your parent was a citizen by registration; and the birth is registered in Zimbabwe in terms of the law
Citizenship By Registration (Section 38)
You can apply to be a Citizen of Zimbabwe by registration if;
(1) You are married to a Zim Zimbabwean citizen for at least five years (after the enactment date), and who satisfies the conditions prescribed by an Act of Parliament,
(2) If one has been continuously and lawfully resident in Zimbabwe for at least ten years, whether before or after the effective date, and who satisfies the conditions prescribed by an Act of Parliament, is entitled, on application, to be registered as a Zimbabwean citizen.
(3) A child who is not a Zimbabwean citizen, but is adopted by a Zimbabwean citizen, whether before or after the effective date, is entitled, on the application, to be registered as a Zimbabwean citizen.
Dual citizenship remains a preserve for citizens by birth. Citizenship by birth cannot be lost or taken away but Citizenship by registration or descent can be taken away.
Section 42(e) limits citizens by registration and by descent from having dual citizenship.