Date | Country | Change |
| 1981 |  Australia | Mission sui juris of Kalumburu was suppressed (to Diocese of Broome) |
| 1981 |  Italy | Territorial Abbacy of San Paolo fuori le Mura lost territory to Papal See of Roma |
| 1981 |  Turkiye | Titular Episcopal See of Tarsus (Greek-Melkite Rite) was promoted as Titular Archiepiscopal See of Tarsus |
| 1981.01.24 |  Nigeria | Diocese of Okigwe was established (from Diocese of Umuahia and became suffragan of Onitsha) |
| 1981.01.24 |  Sri Lanka | Diocese of Mannar was established (from Diocese of Jaffna and became suffragan of Colombo) |
| 1981.01.27 |  USA | Diocese of San Jose was established (from Metropolitan Archdiocese of San Francisco and became suffragan of San Francisco) |
| 1981.01.30 |  Brazil | Diocese of Guarulhos was established (from Diocese of Mogi das Cruzes and became suffragan of São Paulo) |
| 1981.01.30 | Brazil | Diocese of Jardim was established (from Diocese of Corumbá and became suffragan of Campo Grande) |
| 1981.01.30 | Brazil | Diocese of São José dos Campos was established (from Diocese of Mogi das Cruzes and Diocese of Taubaté and became suffragan of Aparecida) |
| 1981.03.11 |  India | Diocese of Ajmer–Jaipur lost territory to Diocese of Indore |
| 1981.03.25 | Italy | Abbacy nullius of Santi Vincenzo ed Anastasio alle Tre Fontane was suppressed (to Papal See of Roma, Diocese of Civita Castellana, Diocese of Nepi and Diocese of Sovana–Pitigliano–Orbetello) |
| 1981.03.25 | Italy | Diocese of Sovana–Pitigliano was renamed as Diocese of Sovana–Pitigliano–Orbetello (gained territory from the suppressed Abbacy nullius of Santi Vincenzo ed Anastasio alle Tre Fontane) |
| 1981.03.28 | Brazil | Diocese of Almenara was established (from Diocese of Araçuaí and Diocese of Teófilo Otoni and became suffragan of Diamantina) |
| 1981.05.27 |  Macau | Diocese of Macau 澳門 lost territory to Archdiocese of Singapore and Diocese of Malacca–Johor |
| 1981.06.21 |  Antigua and Barbuda,  Anguilla,  British Virgin Islands,  Montserrat,  Saint Kitts and Nevis | Diocese of Saint John’s was renamed as Diocese of Saint John’s–Basseterre |
| 1981.07.03 | Brazil,  Mexico,  Uruguay | Apostolic Exarchate of América Latina e México (Armenian Rite) was established |
| 1981.07.03 | USA,  Canada | Apostolic Exarchate of United States of America and Canada (Armenian Rite) was established |
| 1981.07.17 |  Uganda | Diocese of Kiyinda–Mityana was established (from Metropolitan Archdiocese of Kampala and became suffragan of Kampala) |
| 1981.07.30 |  Monaco | Diocese of Monaco was promoted as Archdiocese of Monaco |
| 1981.08.04 | Brazil | Territorial Prelature of Abaeté do Tocantins was promoted as Diocese of Abaetetuba |
| 1981.08.04 | Brazil | Territorial Prelature of Miracema do Norte was promoted as Diocese of Miracema do Norte |
| 1981.08.04 | Brazil | Territorial Prelature of São José do Grajaú was promoted as Diocese of São José do Grajaú |
| 1981.08.04 | Brazil | Territorial Prelature of São Luís de Montes Belos was promoted as Diocese of São Luís de Montes Belos |
| 1981.09.13 |  Egypt | Diocese of Sohag (Coptic Rite) was established (from Diocese of Luqsor and became suffragan of Alexandria) |
| 1981.09.18 |  Poland | Ordinariate of Poland (for Greek and Armenian Catholics) (Eastern Rite) was established (from Metropolitan Archdiocese of Warszawa) |
| 1981.10.03 | Brazil | Territorial Prelature of Santo Antônio de Balsas was promoted as Diocese of Balsas |
| 1981.10.03 | Brazil | Territorial Prelature of Bom Jesus do Piauí was promoted as Diocese of Bom Jesus do Gurguéia |
| 1981.10.03 | Brazil | Territorial Prelature of Guiratinga was promoted as Diocese of Guiratinga |
| 1981.10.03 | Brazil | Territorial Prelature of São Raimundo Nonato was promoted as Diocese of São Raimundo Nonato |
| 1981.10.03 | Poland | Diocese of Sandomierz was renamed as Diocese of Sandomierz–Radom |
| 1981.10.13 | Brazil | Diocese of Guamá was renamed as Diocese of Bragança do Pará |
| 1981.10.21 | Brazil | Diocese of Rio Negro was renamed as Diocese of São Gabriel da Cachoeira |
| 1981.10.28 |  Chile | Diocese of Valparaíso lost territory to Diocese of San Felipe |
| 1981.11.05 |  Rwanda | Diocese of Byumba was established (from Diocese of Kabgayi, Diocese of Kibungo and Diocese of Ruhengeri and became suffragan of Kigali) |
| 1981.11.05 | Rwanda | Diocese of Cyangugu was established (from Diocese of Nyundo and became suffragan of Kigali) |
| 1981.11.06 | Nigeria | Mission sui juris of Abuja was established (from Diocese of Minna) |
| 1981.11.19 | USA | Diocese of Metuchen was established (from Diocese of Trenton and became suffragan of Newark) |
| 1981.12.03 | USA | Diocese of Van Nuys (Ruthenian Rite) was established (from Diocese of Parma and became suffragan of Pittsburgh) |
| 1981.12.19 |  Liberia | Apostolic Vicariate of Cape Palmas was promoted as Diocese of Cape Palmas (became suffragan of Monrovia) |
| 1981.12.19 | Liberia | Apostolic Vicariate of Monrovia was promoted as Metropolitan Archdiocese of Monrovia (with suffragan see Cape Palmas) |
