Trinity College has its origins in Christian Brothers’ College, St George’s Terrace Perth, founded by Bishop Mathew Gibney and Brother Ambrose Treacy in 1894.

The Brothers at CBC also operated a nearby school, St Patrick's, and the history of the two schools ran in parallel until St Patrick's was closed.

From the 1890's, both boarders and day students were enrolled at CBC. However, as the business section of the city expanded, the site became increasingly unsuitable for a boarding school and the Brothers examined a number of sites that would be suitable for boarders.

Finally, in 1938, the boarders and some day students were transferred to Mount Henry, Manning, to found Aquinas College.

Christian Brothers’ College continued as a school for boys only on the St George's Terrace site.

In 1961, the buildings and land were purchased by the Perth City Council as the site was considered ideal for the construction of a major hotel to be ready for the Empire games. The College was transferred to its present location in 1962 and renamed Trinity College. (more information)

In 1968 Trinity became a member of the Public Schools Association of Western Australia - a sporting association that had been formally established in 1905.

During its time as CBC, most teachers were Brothers. Following the move to East Perth, an increasing number of lay teachers were employed.

In 1994 the first lay principal was appointed. Today all classroom teachers are lay teachers.