International youth holiday resorts feature many of the key risk factors for violence, including large numbers of bars and nightclubs and high levels of substance use. However, little information currently exists on the extent of violence amongst holidaymakers or factors that increase risks of involvement in fights on holiday. A cross-sectional comparative survey of 3003 British, German and Spanish holidaymakers aged 16-35 years, undertaken in the departure areas of Ibiza and Majorca (Spain) airports. Nightlife was the most common reason for destination choice in both locations. Overall, more than half of participants reported drinking to drunkenness at least 2 days per week during their holiday (59.3% Majorca, 58.0% Ibiza; significantly lower in Spanish participants in both locations). Levels of illicit drug use were highest in Ibiza and in British and Spanish holidaymakers. Levels of violence were highest in Majorca, where 6.4% of participants reported involvement in a fight, compared with 2.8% in Ibiza. However, after controlling for confounding factors, holiday destination was not a significant predictor of violence. Predictors of fighting were being male, young, British, frequent drunkenness and use of cannabis or cocaine during the holiday. Use of ecstasy on holiday was associated with not being involved in violence. High levels of substance use contribute to violence being a relatively common feature of young people's visits to international holiday resorts. To protect the health and well-being of holidaymakers and local populations in popular resorts, violence and substance use prevention must adapt to an increasingly globalized nightlife.