Prepartying and drinking game playing are associated with excessive alcohol consumption and alcohol-related negative consequences in college populations; however, research exploring the prevalence of these high risk drinking contexts among high school students, and how such engagement may impact both high school and subsequent college drinking risk, is lacking. The current study, which is the first study to assess prepartying during high school, examined how engaging in either prepartying or drinking game playing during high school was associated with risky high school drinking as well as alcohol use and consequences during the transitional first month of college. The study involved 477 first-year college students, the majority of whom were 18 years old (94%), female (66%), and Caucasian (59%). Prepartying was found to be highly prevalent in high school (45%). Further, students who prepartied or played drinking games during high school drank significantly more in high school than students who did not engage in these high risk activities. Finally, prepartying and game playing during high school were associated with greater collegiate alcohol consumption (controlling for high school drinking) and consequences (controlling for both high school and college drinking). This study establishes prepartying and drinking games as common high risk activities among both high school and incoming first-year college students, and addresses implications for prevention and targeted interventions.