Cornish College is part of the Southern Independent Schools network of fifteen schools offering regular interschool sporting and cultural competitions throughout the school year.

Sports include athletics, cross country, swimming, baseball, basketball, cricket, football, handball, lawn bowls, netball, soccer, softball, table tennis, tennis, touch rugby and volleyball.

Cultural events include chess, debating, drama/TheatreSports, Teen Chef, Book in a Day and public speaking championships.