The high school is a member of the Los Angeles Athletic Association (LAAA) under the California Interscholastic Federation and the Catholic Athletic Association.
Available seasonal sports are:
- Fall: Cross Country, Tennis, Volleyball
- Winter: Basketball, Soccer
- Spring: Diving, Softball, Swimming, Track & Field
- All-Year: Equestrian
The Athletic Department, along with the student leaders in the Girls' Athletic Association, coordinate themed pep rallies at the beginning of each sports season to announce team members. Cheers, games and school spirit activities are held throughout the year. At the end of each season, the Athletic Department provides an evening banquet to honor athletes and coaches. An annual spring luncheon honors all scholar athletes who maintain a 3.5 or higher grade point average. Approximately one third of high school students participate on one or more teams at Immaculate Heart, and more than half are scholar athletes.