The relationship between tourism and events has been widely studied, with a focus on visitor motivations, behaviors, and the socioeconomic impacts of hosting events. However, research on visitor expenditure during events remains limited and often relies on survey-based approaches, typically centered on willingness to pay. The present study adopts an approach for aggregated big data, primarily using Mastercard credit card transaction and Vodafone mobility data, to analyze actual visitor expenditure. Focusing on the Venice International Film Festival, a prestigious cultural event held in one of Europe’s most visited destinations, this research applies a spatiotemporal econometric model to examine the expenditure patterns of four visitor clusters: domestic, cross-border, consumer, and commercial cardholders. The findings reveal the diverse economic impacts that a cultural event can generate, highlighting variations in expenditures across visitor types and locations in Venice during the event period.