| Date | Country | Change |
| 1980 | Titular Episcopal See of Anbar (Chaldean Rite) was established | |
| 1980 | Titular Metropolitan See of Apamea in Syria (Greek-Melkite Rite) was established | |
| 1980 | Titular Archiepiscopal See of Cesarea in Cappadocia (Greek-Melkite Rite) was established | |
| 1980.01.20 | Diocese of Oppido Mamertina–Palmi lost territory to Metropolitan Archdiocese of Reggio Calabria | |
| 1980.01.25 | Territorial Prelature of Deán Funes was established (from Diocese of Cruz del Eje and became suffragan of Córdoba) | |
| 1980.01.29 | Diocese of Lake Charles was established (from Diocese of Lafayette in Louisiana and became suffragan of New Orleans) | |
| 1980.02.02 | Diocese of Novo Hamburgo was established (from Metropolitan Archdiocese of Porto Alegre and became suffragan of Porto Alegre) | |
| 1980.02.04 | Priory nullius of Ciudad Real was promoted as Diocese of Ciudad Real (became suffragan of Toledo) | |
| 1980.02.14 | Diocese of Great Falls was renamed as Diocese of Great Falls–Billings | |
| 1980.03.03 | Titular Episcopal See of Asidonia was suppressed (to establish Diocese of Jerez de la Frontera) | |
| 1980.03.03 | Diocese of Jerez de la Frontera was established (from Metropolitan Archdiocese of Sevilla and Diocese of Cádiz y Ceuta, from the suppressed Titular Episcopal See of Asidonia and became suffragan of Sevilla) | |
| 1980.03.06 | Apostolic Prefecture of Meki was established (from Apostolic Vicariate of Harar) | |
| 1980.03.06 | Diocese of Muzaffarpur was established (from Diocese of Patna and became suffragan of Ranchi) | |
| 1980.03.06 | Diocese of Hamilton was established (from Diocese of Auckland and became suffragan of Wellington) | |
| 1980.03.06 | Diocese of Palmerston North was established (from Metropolitan Archdiocese of Wellington and became suffragan of Wellington) | |
| 1980.03.14 | Diocese of Itaguaí was established (from Diocese of Barra do Piraí–Volta Redonda and Diocese of Nova Iguaçu and became suffragan of São Sebastião do Rio de Janeiro) | |
| 1980.03.27 | Diocese of Chascomús was established (from Metropolitan Archdiocese of La Plata and Diocese of Mar del Plata and became suffragan of La Plata) | |
| 1980.03.28 | Diocese of Imphal was established (from Diocese of Kohima–Imphal and became suffragan of Shillong–Gauhati) | |
| 1980.03.28 | Diocese of Kohima–Imphal was renamed as Diocese of Kohima (lost territory to establish Diocese of Imphal) | |
| 1980.03.28 | Apostolic Administration of Zanzibar and Pemba was promoted as Diocese of Zanzibar (became suffragan of Dar-es-Salaam) | |
| 1980.04.14 | Diocese of Assisi lost territory to Archdiocese of Spoleto | |
| 1980.04.23 | Diocese of Cairo (Chaldean Rite) was established (without ecclesiastical province) | |
| 1980.05.30 | Diocese of Hallam was established (from Diocese of Leeds and Diocese of Nottingham and became suffragan of Liverpool) | |
| 1980.06.07 | Diocese of Bubanza was established (from Diocese of Bujumbura and became suffragan of Gitega) | |
| 1980.06.28 | Diocese of Benjamín Aceval was established (from Diocese of Concepción and Apostolic Vicariate of Pilcomayo and became suffragan of Asunción) | |
| 1980.07.29 | Diocese of Mobile was promoted as Metropolitan Archdiocese of Mobile (with suffragan sees Biloxi, Birmingham and Jackson) | |
| 1980.10.11 | Diocese of Duque de Caxias was established (from Diocese of Nova Iguaçu and Diocese of Petrópolis and became suffragan of São Sebastião do Rio de Janeiro) | |
| 1980.10.11 | Diocese of Guarabira was established (from Metropolitan Archdiocese of Paraíba and became suffragan of Paraíba) | |
| 1980.10.11 | Territorial Prelature of Tagum was promoted as Diocese of Tagum | |
| 1980.10.13 | Diocese of Saint-Sauveur de Montréal (Greek-Melkite Rite) was established (without ecclesiastical province) | |
| 1980.10.13 | Diocese of Saints Cyril and Methodius of Toronto (Slovak Rite) was established | |
| 1980.10.15 | Ordinariate of Ordinariaat voor buitenlandse studenten in België was suppressed | |
| 1980.10.20 | Metropolitan Archdiocese of Brindisi was demoted as Archdiocese of Brindisi (became suffragan of Lecce) | |
| 1980.10.20 | Diocese of Lecce was promoted as Metropolitan Archdiocese of Lecce (with suffragan sees Brindisi, Otranto, Gallipoli, Nardò, Ostuni and Ugento–Santa Maria di Leuca) | |
| 1980.10.20 | Metropolitan Archdiocese of Otranto was demoted as Archdiocese of Otranto (became suffragan of Lecce) | |
| 1980.10.20 | Metropolitan Archdiocese of Trani was demoted as Archdiocese of Trani (became suffragan of Bari e Canosa) | |
| 1980.10.24 | Apostolic Prefecture of Sibolga was promoted as Diocese of Sibolga (became suffragan of Medan) | |
| 1980.10.30 | Territorial Prelature of Macapá was promoted as Diocese of Macapá | |
| 1980.10.30 | Territorial Prelature of Parintins was promoted as Diocese of Parintins | |
| 1980.10.30 | Territorial Prelature of Rio Negro was promoted as Diocese of Rio Negro | |
| 1980.10.30 | Territorial Prelature of Tocantinópolis was promoted as Diocese of Tocantinópolis | |
| 1980.11.22 | Apostolic Vicariate of San Francisco Javier was renamed as Apostolic Vicariate of Jaén en Perú | |
| 1980.11.29 | Diocese of Orlu was established (from Diocese of Owerri and became suffragan of Onitsha) | |
| 1980.11.29 | Diocese of Soroti was established (from Diocese of Tororo and became suffragan of Kampala) |
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