The diocese was founded in 739 by Saint Boniface;[1] it was originally subordinate to the archbishop of Salzburg.

In the 13th century, the bishop of Regensburg became a prince of the Holy Roman Empire with a seat and vote at the Imperial Diet.

As an enclave of the Duchy of Bavaria, the prince-bishopric was not able to expand territorially and remained one of the smallest of the Empire.

In 1810, the principality became part of the Kingdom of Bavaria, although it retained archiepiscopal status.

The Bavarian Concordat of 1817 following Dalberg's death downgraded the Archdiocese of Regensburg into a suffragan diocese subordinate to the archbishop of Munich and Freising.