The Roman Catholic Diocese of Blumenau () is a diocese located in the city of Blumenau in the ecclesiastical province of Joinville in Brazil.
History April 19, 2000: Established as Diocese of Blumenau from the Metropolitan Archdiocese of Florianópolis, Diocese of Joinville and Diocese of Rio do Sul November 5, 2024: The diocese became a suffragan see of the newly promoted Archdiocese of Joinville
Leadership Bishops of Blumenau (Roman rite) Bishop Angélico Sândalo Bernardino (April 19, 2000 – February 18, 2009) Bishop Giuseppe Negri, P.I.M.E., (February 18, 2009 – October 29, 2014), appointed Coadjutor Bishop of Santo Amaro, São Paulo Bishop Rafael Biernaski (June 24, 2015 – present)
References GCatholic.org Catholic Hierarchy Diocese website (Portuguese)