Bali Island School is an active member of the Bali Schools Sports Association (BSSA), which is a group of international and National Plus schools who are working together to promote and implement friendly sporting competitions among schools in Bali. Inter School competitions currently running are: football (soccer), cross-country, volleyball, athletics, swimming and basketball.

BIS is also a member school of IISSAC (Indonesian International Small Schools Activities Council). This is an opportunity for BIS students to represent BIS in Football, Basketball and Swimming and to travel to, and compete against, other International schools from around Indonesia.

Other sports offered at Bali Island School include: tennis, softball, AFL, rugby, touch rugby, badminton, Ultimate, water polo, gymnastics/dance, athletics and swimming.