The priority system and assigned dates
Registration dates are set using a priority system: those closest to completing a degree are afforded the first opportunities to enroll. New transfer students and freshmen, regardless of hours completed, register last. Popular classes do fill quickly so don't wait until just before classes start to register.
Watch the Academic Calendar for a link to general information about registration dates. Registration for the next semester typically begins about a month before the end of the current term. Your assigned registration date will also appear in your portal under "Term Information".