A wide range of supervised sports are available and these include athletics, cricket, tennis, swimming, life-saving, netball, table tennis, hockey, basketball, volleyball, badminton, water polo, underwater hockey, cross country, softball, rowing, soccer, touch rugby and skiing, All students are encouraged to participate in sports and there are opportunities to play for St Mary's College teams in regular competitions with other colleges and clubs in the Wellington area. Where sport is offered in the College as an extra-curricular activity, students are expected to play for the College as often as possible. The college has a long and strong tradition in these cultural pursuits. Both Art and Music are taught at all levels and may be taken for School Certificate, Sixth Form Certificate, University Bursaries and Scholarship examinations. In the Art room complex the students' talents are developed and extended.
Students participate successfully in many competitions.
With additional music practice rooms and expert music teachers, both permanent and itinerant, opportunities are available for students to learn a wide range of instruments free of charge. Students may join the school orchestra, ensemble or choirs. Drama is also an integrated part of the curriculum. The college aims to perform a major production each year and opportunity is given to all interested students to participate.