A diocese is a portion of the people of God within a geographical area, entrusted to the pastoral care of a Bishop (Bishop David Walker), who is assisted in his ministry by priests, deacons, and his Curia. The diocese remains close to its pastor and is gathered by him through the Gospel and the Eucharist in the Holy Spirit to constitute a particular local church. In this Church, the one, holy, catholic and apostolic Church of Christ truly exists and functions. (cf. Code of Canon Law, 369)

The Catholic Diocese of Broken Bay exists to serve the People of God in the northern regions of the city of Sydney, including the North Shore, Peninsula and NSW Central Coast.

Mission Statement for Broken Bay
In 1999, the Diocese underwent the beginnings of an intensely collaborative process to define a Pastoral Plan for its future and assist in clarifying a true sense of identity for the faith community. The first stage was to develop a Diocesan Mission Statement, which was launched by Bishop David in Lent 2000.

Diocesan Pastoral Plan 
After the completion of the first phase of Diocesan-wide planning, the second phase was put into action - a Diocesan consultative process that would discern how the people of Broken Bay would live out their Mission Statement. This saw the launch in September 2001 of the Diocesan Pastoral Plan; Going Forward Together 2001-2005. As a direct response to its call, Parishes, schools, Diocesan agencies and special ministry areas were asked to develop their own plans reflecting the Diocesan goals and achievement targets, whilst taking into account their own situations and special priorities.

In 2006, again after much consultation, assessment and collaboration, the next phase of Diocesan planning was launched with the Pastoral Plan: Going Forward Together, Pastoral Care for Evangelisation 2006-2010. The essential focus was to build on the strong foundations of its precursor and to develop practices and structures which will ensure that all Catholics within Broken Bay Diocese will have access to, and receive the best possible Pastoral Care available.