The High School at Cayman International School consists of grades 9 to 12. The curriculum is based on American and International standards and is designed to prepare students for entrance into colleges or universities around the world. In order to graduate from CIS, students must complete a specific number of credits in core subjects and elective courses. The graduation requirements ensure a holistic learning experience that prepares students to be well-rounded, knowledgeable, and passionate learners. Course completion and credit accumulation require passing marks and regular attendance.

Qualified students in grades 11 and 12 are able to take courses in the International Baccalaureate Diploma Programme (IBDP). The IBDP provides a holistic learning experience, and subject specific course work prepares students for external exams given around the world in May of each year. Successful performance on IB subject exams and the IB diploma can lead to advanced standing in universities and colleges in North America, Europe, and other regions of the world.

CIS promotes an active homeroom/advisory program. All students are part of a homeroom, and homeroom teachers serve as an advisor to provide academic and pastoral support. Homeroom teachers, in addition to counselors, assist students with goal setting, study skills, service learning, team building, and social/emotional support. Homeroom teachers provide additional information and support related to high school specific issues (graduation requirements, college and career exploration, portfolio development, and the college application process). Homeroom teachers are also the key contact for parents and provide valuable school to home communication.