If her father remains of a different religion than that of the daughter at the time of the marriage contract, he has no authority over her. In this case, guardianship transfers to her nearest Muslim relative by blood. If there is none, then the guardian is the ruler [or local authority] of the one who has no guardian, which in this case would be the Imam of the mosque.

However, if she remains on her religion at the time of the marriage contract, her father is her guardian according to the majority opinion. He can give his consent in any form, written or over the phone, as long as it is confirmed.

There is also an opinion held by some jurists that a non-Muslim cannot have guardianship in an Islamic marriage, even over his own daughter who is a Dhimmī (non-Muslim under Muslim rule). Instead, guardianship automatically transfers to a Muslim guardian because guardianship is a judicial and religious act that can only be carried out by someone who is legally accountable in Islam. Based on this, her guardian would also be the Imam of the mosque.

It is also permissible according to the Ḥanafī school of Islamic law for her to marry with her own consent and guardianship.

Fatwā issued by Dr. Khālid Naṣr