The following dioceses have seminarians in formation at St. John Vianney Theological Seminary:

Archdiocese of Denver
Diocese of Bismarck
Diocese of Cheyenne
Diocese of Dallas
Diocese of Dodge City
Diocese of Fargo
Diocese of Gallup
Diocese of Helena
Archdiocese of Kansas City – Kansas
Archdiocese of Oklahoma City
Diocese of Phoenix
Diocese of Sioux City
Diocese of Bui Chu, Vietnam
Diocese of Kasana-Luweero, Uganda
Diocese of Yangon, Myanmar