The Roman Catholic Diocese of Coari (Latin: Dioecesis Coaritana) is a diocese located in the city of Coari in the ecclesiastical province of Manaus in Brazil.

The Roman Catholic Diocese of Coari was erected on 9 October 2013 by Pope Francis, and is a part of the Ecclesiastical Province of the Roman Catholic Archdiocese of Manaus, based in Manaus, Brazil.

It has been led since its elevation by its first bishop, Marek Marian Piatek, C.Ss.R., a Polish native and a member of the Congregation of the Most Holy Redeemer (the Redemptorists).

• July 13, 1963, the Territorial Prelature of Coari was established from the Metropolitan Archdiocese of Manaus.
• October 9, 2013: Promoted as Diocese of Coari

• Prelates of Coari (Latin Church)
  • Mário Roberto Emmett Anglim, C.Ss.R. (April 24, 1964 – April 13, 1973)
  • Gutemberg Freire Régis, C.Ss.R. (July 23, 1978 – February 28, 2007)
  • Joércio Gonçalves Pereira, C.Ss.R. (coadjutor 2005–2007; bishop February 28, 2007 – July 22, 2009)
  • Marek Marian Piatek, C.Ss.R. (August 12, 2011 – October 9, 2013)
• Bishops of Coari
  • Marek Marian Piatek, C.Ss.R. (October 9, 2013–present)

• GCatholic.org
• Catholic Hierarchy

4°05′S 63°08′W / 4.083°S 63.133°W / -4.083; -63.133