To what extent do people participate more if they have a larger supply of political protest around them? Can supply contribute to reduce inequalities in participation? We explore how the supply of protest events mobilizes individuals to participate in demonstrations by geo-localizing both individuals and events. We expand on the existing literature on individual demonstrators and staging organisations by focusing our attention on the relationship between individual characteristics and their protest environments. Cross-level analyses from a representative survey of Barcelona and protest event data between 2010 and 2016 show that both distance to protest events and density of contentious activity is relevant in explaining participation in protest, and that supply effects are significant for individuals with low income levels. Furthermore, we confirm that issue importance and sympathy for staging organizations strengthen supply effects.