Date | From | To |
unknown | Vicariate Apostolic of Nyanza, Uganda
| Name Changed | Vicariate Apostolic of Victoria-Nyanza, Uganda
| Name Changed |
unknown | | | Vicariate Apostolic of Tanganyika, Tanzania (to Vicariate Apostolic)
| Elevated |
unknown | | | Clerical Public Association of La Hermandad de Sacerdotes Operarios Diocesanos del Sagrado Corazón de Jesús
| Founded |
5 Mar | Vicariate Apostolic of Idaho and Montana, USA
Vicariate Apostolic of Nebraska, USA
| Territory Lost | Vicariate Apostolic of Montana, USA
| Erected |
5 Mar | Vicariate Apostolic of Idaho and Montana, USA
| Name Changed | Vicariate Apostolic of Idaho, USA
| Name Changed |
11 Mar | Archdiocese of Saint Louis, Missouri, USA
| Territory Lost | Vicariate Apostolic of Montana, USA (Current part of the state of Montana East of the Rockies)
| Territory Added |
7 Apr | Diocese of Bulgarian United Church (Constantinople) (Bulgarian)
| Territory Lost | Vicariate Apostolic of Tracia (Hadrianopolis) (Bulgarian), Turkey
| Erected |
20 Apr | Diocese of Colombo, Sri Lanka
| Territory Lost | Vicariate Apostolic of Kandy, Sri Lanka
| Erected |
27 Apr | Apostolic Administration of Nicopolis, Romania
| Elevated | Archdiocese of Bucarest {Bucureşti}, Romania
| Elevated |
24 May | Diocese of Sonora, México
| Territory Lost | Diocese of Sinaloa, México
| Erected |
1 Jun | Vicariate Apostolic of Eastern Tonking {Tonkino Orientale}, Viet Nam
| Territory Lost | Vicariate Apostolic of Northern Tonking {Tonkino Settentrionale}, Viet Nam
| Erected |
5 Jun | Diocese of Galway, Ireland
Diocese of Kilmacduagh, Ireland
Diocese of Kilfenora, Ireland
| United | Diocese of Galway and Kilmacduagh, Ireland
| United |
12 Jun | Diocese of Bulgarian United Church (Constantinople) (Bulgarian)
| Territory Lost | Vicariate Apostolic of Macedonia (Thessalonika) (Bulgarian)
| Erected |
26 Jun | Vicariate Apostolic of Costa di Benin, Nigeria
| Territory Lost | Prefecture Apostolic of Dahomey, Benin
| Erected |
10 Jul | | | Eparchy of Musc (Mush) (Armenian), Armenia
| Erected |
16 Nov | | | Prefecture Apostolic of Southern Patagonia, Tierra del Fuego, and Islas Malvinas, Chile
| Erected |
23 Nov | Prefecture Apostolic of Zanguebar, Kenya
| Elevated | Vicariate Apostolic of Zanguebar, Kenya
| Elevated |
3 Dec | Vicariate Apostolic of Fo-Kien, China
| Territory Lost | Vicariate Apostolic of Amoy, China
| Erected |
21 Dec | Vicariate Apostolic of Mongolia, China
| Territory Lost | Vicariate Apostolic of Southwestern Mongolia {Mongolia Occiduo-Meridionale}, China
Vicariate Apostolic of Eastern Mongolia {Mongolia Orientale}, China
| Erected |
21 Dec | Vicariate Apostolic of Mongolia, China
| Name Changed | Vicariate Apostolic of Central Mongolia {Mongolia Centrale}, China
| Name Changed |