1892 - Present
- 1892 - An English Barrister, E P Field, preaches to lunch-hour crowds in Martin Place, Sydney, Australia, and forms the NSW (New South Wales) Prayer Band to support this ministry.
- 1913 - The NSW Prayer Band is renamed the NSW Evangelistic Prayer Band.
- 1921 - Former missionary W Bradley joins the NSW Evangelistic Prayer Band.
- 1922 - W Bradley changes the name to 'Open Air Campaigners'. Gospel wagons are used to take the gospel message to people throughout NSW, Australia.
- 1939 - OAC works among the armed services during World War II.
- 1940 - 1950 - The work extends to the states of Queensland, Victoria, South Australia and overseas.
- 1956 - OAC USA and OAC Canada founded by Jim Duffecy.
- Today - OAC Ministries operates in five states of Australia and 30 countries worldwide. Many of our countries use OAC as an acronym, Outreach and Church Ministries, instead of "Open Air Campaigners" as the name is often confused with political campaigns. The ministry in Canada is called OAC Ministries Canada.