There are limitations in determining the economic impact of sporting events that need to be considered. One of these is represented by first-round leakages. This work focuses on explaining first-round leakages in the economic impact of sporting events on small cities. Seeking to identify this type of leakage, we estimated the spatial distribution of the economic impact of two small-sized events organized in a town with a population of 24,248 inhabitants. The results showed a first-round leakage exceeding €300,000 and identified higher average attendee expenditure in a more developed city adjacent to the host city. Moreover, an exploratory analysis concerning the influence of leakage in final spending was performed. Finally, the elements that would increase the probability of leakage were studied. Overall, the current case study highlighted the importance of considering the existence of leakage.