Cardiff High School became a seven form entry school in September 1998, when a third feeder primary school, Roath Park, was added to the two existing feeder schools, Lakeside and Rhydypenau. In 2011, Marlborough Primary was added as a fourth partner school (the 'Feeder School' criterion no longer being considered for admission purposes) as the school increased to an eight form intake. As of 2016, it has a total pupil roll of 1635, of whom 450 are in the sixth form.