As soon as new cadets arrive on R-Day, they begin to experience the military environment ever present at the academy. They are required to conduct themselves according to military standards and render proper military courtesies. The first phase of military training is conducted during the six-week program known as Cadet Basic Training (CBT). Cadet Basic Training, or Beast Barracks, is one of the most strenuous and intense periods of training that cadets encounter while at the academy.

During CBT, upper-class instructors, tactical officers and noncommissioned officers educate and train new cadets in basic soldier skills and prepare them for acceptance into the Corps of Cadets. In addition, the program is designed to inspire each new cadet to internalize the ideals of West Point and the Army. Along with instruction in military subjects, new cadets participate in drills, marches and overnight field training.

Cadet Basic Training culminates in a week of training and living in a field environment and a 15-mile march back to West Point. The new cadets, led by the USMA Band, are greeted by well-wishers lining the streets as they pass-in-review before the Superintendent and senior members of the staff. Soon after, they are accepted into the Corps and acknowledged as plebes in a brigade ceremony on the Plain.