The St Mary's campus is in West Melbourne located five minutes away from Queen Victoria Market.

Simonds was formed in 1996 through the amalgamation of Cathedral College, East Melbourne, and St Mary's Boys School.

In 2010, the former St Brigid's Primary School in North Fitzroy was renovated, and a new senior campus of the college was opened there.

Smaller events include ACC Sports (Basketball, Football, Lawn Bowls, Table Tennis, Badminton, Volleyball).

High-performing students in these events are selected to represent the school in the Associated Catholic Colleges Swimming and Athletics Championships.