St. Anthony's High School organises a number of Inter-school Competitions, including:

ORATIO: The Inter-School Elocution Contest

LET’S GET QUIZICAL: The Inter-School Quiz Contest

THE GROOVE: The Inter-School Dance Competition

SHOOTING HOOPS: The Inter-School Basketball Tournament

Students, whenever possible are offered the opportunity of competitions and encouraged to take part in them. At inter-school events our pupils are provided an opportunity to meet and compete with other schools, assess their strengths and weakness within the Kolkata student community, showcase talent, improve their performances and be inspired to achieve success. Besides organising the above events, the school also participates in the inter-school activity organised by other city schools.