BACKGROUND: Recent research has highlighted the growing trend of alcohol preloading before a night out. We wished to look at people's motivations for preloading, their estimation for drinking during the night, and assess the impact that preloading has on how inebriated people become across the night as measured by Breath Approximated blood Alcohol Content (BrAC). METHOD: We randomly surveyed and breath-tested patrons as they entered and exited Night Time Entertainment Districts (NEDs) in Brisbane, Queensland. We obtained 360 participants who were encouraged to contact us at the end of their night, compensating them for their time with a taxi voucher. Of these, 143 people returned and completed an exit questionnaire. FINDINGS: We found that people were motivated to preload in order to save money and socialise, were likely to drink more than they predicted over the course of the night, and were more surprised by their alcohol reading the higher their BrAC; this trajectory displayed little difference between men and women. It was further found that, for men, personality contributed 19% of the variance to exit BrAC, but entry BrAC accounted for nearly 38% of unique variance. For women, body mass index significantly predicted exit BrAC (9% unique variance), but entry BrAC accounted for nearly 30% unique variance. INTERPRETATION: To reduce general levels of intoxication in city NEDs, interventions should focus on having people come in earlier, less drunk, and be taught to have more realistic appraisals of their drinking.