The annual festivities began Thursday night on UConn's Storrs campus. Police have announced extra patrols, limits on non-student visitors and roadblocks at many campus entries.
UConn police arrested eight people and state troopers arrested three others late Thursday and early Friday. The charges ranged from marijuana and alcohol offenses to weapons violations.
Dozens of traffic tickets, warnings and infractions were also issued.
Officials want to prevent a repeat of last year's problems, in which a student died after being punched at an off-campus restaurant. An East Hartford man awaits trial in the case.
UConn has struggled for years to subdue rowdy Spring Weekend revelry.