The school, located in three adjoining buildings at 53-55 St. Stephen's Green, has a city centre location. However, the majority of its students, drawn from a wide geographical area, largely come from the north and south Dublin suburbs, north County Dublin and County Meath. These have been the traditional catchment areas for the school over many years.

Each year, approximately thirty students from the Loreto Junior School (on the same site) enter first year, making up about one-third of the annual intake. There is a small intake of students, generally from other schools, into other classes, when vacancies exist. Loreto College is a traditional school in that families, over generations, have tended to send their daughters there.

Ninety-six girls are admitted to the new first year each autumn. They are divided into four class groups and this remains the pattern for the school. Class size remains at this level and year groups in the school do not exceed ninety-six students.