Changes in Ecclesiastical Jurisdictions in Thailand

Date	Change
1662	Apostolic Vicariate of Siam was established (from Apostolic Vicariate of Cochin and Apostolic Vicariate of Tonking)
1841.09.10	Apostolic Vicariate of Siam was renamed as Apostolic Vicariate of Eastern Siam (lost territory to establish Apostolic Vicariate of Western Siam)
1899.05.04	Apostolic Vicariate of Laos was established (from Apostolic Vicariate of Eastern Siam)
1924.12.03	Apostolic Vicariate of Eastern Siam was renamed as Apostolic Vicariate of Bangkok
1930.06.30	Mission sui juris of Rajaburi was established (from Apostolic Vicariate of Bangkok)
1934.05.28	Mission sui juris of Rajaburi was promoted as Apostolic Prefecture of Rajaburi
1941.04.03	Apostolic Prefecture of Rajaburi was promoted as Apostolic Vicariate of Rajaburi
1944.05.11	Apostolic Vicariate of Chantaburi was established (from Apostolic Vicariate of Bangkok)
1950.12.21	Apostolic Vicariate of Laos was renamed as Apostolic Vicariate of Thare (lost territory to establish Apostolic Prefecture of Thakhek)
1953.05.07	Apostolic Vicariate of Ubon was established (from Apostolic Vicariate of Thare)
1953.05.07	Apostolic Prefecture of Udonthani was established (from Apostolic Vicariate of Thare)
1959.11.17	Apostolic Prefecture of Chieng-Mai was established (from Apostolic Vicariate of Bangkok)
1960.03.25	Apostolic Vicariate of Thare was renamed as Apostolic Vicariate of Thare and Nonseng
1965.03.22	Apostolic Vicariate of Nakhorn-Rajasima was established (from Apostolic Vicariate of Ubon)
1965.12.18	Apostolic Vicariate of Bangkok was promoted as Metropolitan Archdiocese of Bangkok (with suffragan sees Bangnokhuek, Chantaburi and Chieng-Mai)
1965.12.18	Apostolic Vicariate of Rajaburi was promoted as Diocese of Bangnokhuek (became suffragan of Bangkok)
1965.12.18	Apostolic Vicariate of Chantaburi was promoted as Diocese of Chantaburi (became suffragan of Bangkok)
1965.12.18	Apostolic Prefecture of Chieng-Mai was promoted as Diocese of Chieng-Mai (became suffragan of Bangkok)
1965.12.18	Apostolic Vicariate of Nakhorn-Rajasima was promoted as Diocese of Nakhorn-Rajasima (became suffragan of Thare and Nonseng)
1965.12.18	Apostolic Vicariate of Thare and Nonseng was promoted as Metropolitan Archdiocese of Thare and Nonseng (with suffragan sees Nakhorn-Rajasima, Ubon and Udonthani)
1965.12.18	Apostolic Vicariate of Ubon was promoted as Diocese of Ubon (became suffragan of Thare and Nonseng)
1965.12.18	Apostolic Prefecture of Udonthani was promoted as Diocese of Udonthani (became suffragan of Thare and Nonseng)
1966.10.21	Diocese of Bangnokhuek was renamed as Diocese of Ratburi
1967.02.09	Diocese of Nakhorn-Sawan was established (from Metropolitan Archdiocese of Bangkok and became suffragan of Bangkok)
1969.06.26	Diocese of Ratburi was renamed as Diocese of Ratchaburi (lost territory to establish Diocese of Surat Thani)
1969.06.26	Diocese of Surat Thani was established (from Diocese of Ratburi and became suffragan of Bangkok)
1969.07.02	Diocese of Chantaburi was renamed as Diocese of Chanthaburi
1969.07.02	Diocese of Chieng-Mai was renamed as Diocese of Chiang Mai
1969.07.02	Diocese of Nakhorn-Rajasima was renamed as Diocese of Nakhon Ratchasima
1969.07.02	Diocese of Nakhorn-Sawan was renamed as Diocese of Nakhon Sawan
1969.07.02	Diocese of Ubon was renamed as Diocese of Ubon Ratchathani
1969.07.02	Diocese of Udonthani was renamed as Diocese of Udon Thani
1970.06.20	Diocese of Chiang Mai lost territory to Diocese of Nakhon Sawan
2018.04.25	Diocese of Chiang Rai was established (from Diocese of Chiang Mai and became suffragan of Bangkok)