Objective. The aim of the present study was to explore whether constructs within the Prototype Willingness Model (PWM) predicted risky drinking as measured by AUDIT-C, drinking harms and unplanned drunkenness in a sample of UK young adults. Previous studies exploring the PWM often do not use validated measures of alcohol consumption, and the outcomes of risky drinking are underexplored. Design. An online prospective study design with four week follow up was employed and 385 young adults completed the study (M age = 21.76, SD = 3.39, 69.6% female; 85.2% students). Main outcome measures. Intentions to get drunk, AUDIT-C, drinking harms experienced in the last four weeks, and unplanned drunkenness in the last four weeks. Results. Heavy and non-drinker prototype similarity predicted AUDIT-C, drinking harms and unplanned drunkenness when controlling for past behaviour and reasoned action pathway constructs. Intentions and willingness both mediated the relationship between prototype perceptions and AUDIT-C. Conclusion. This study supports the use of the PWM in the prediction of AUDIT-C, drinking harms and unplanned drinking in a UK sample. Prototype perceptions influenced behaviour via both reasoned and reactive cognitions. Targeting similarity to heavy and non-drinker prototypes should be the focus of future interventions in this population