1892  - An English Barrister, E P Field, preaches to lunch-hour crowds in Martin Place, Sydney, Australia, and forms the NSW 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 nineteen countries worldwide.