Proof of baptism is normally established by a certificate of baptism issued by the church where the baptism took place.
For Catholic Baptisms in a U.S. Military Chapel
Those who celebrated their baptism in a military or VA chapel anywhere in the world may submit an online request for their baptismal certificate through the AMS website. Note that this process can take time, so it is best to make the request at the beginning of the preparation process.
For Catholic Baptisms in a Civilian Parish
Those who celebrated baptism in a civilian parish must contact that particular parish to request a copy of their baptismal certificate.
For Non-Catholic Baptisms
Some non-Catholic Christian denominations keep records of those baptized in their churches. When contacted about proof of baptism, they may issue a certificate, or letter, or even a copy of the register page proving the person’s baptism.
If the Christian denomination does not provide baptism certificates or no longer exists, evidence of a person’s baptism can be provided by means of a written affidavit from one or two persons who witnessed the Christian baptism, e.g., parents, aunts or uncles, older siblings, or friends. Please contact the AMS Judicial Vicar for the details in writing an affidavit.