While today Brazil is the world’s number three country with the highest number of municipalities with fare-free public transport (FFPT) in place, research about the motivations and characteristics behind ‘Tarifa Zero’, as the policy is called across Brazil, remains limited. In the framework of a collaborative research project, we conducted fieldwork in 15 selected municipalities throughout March and April 2022, combining semi-structured interviews with governmental representatives and key actors involved in the process of applying FFPT. The main aim of our research is to understand better the motivations behind FFPT, as well as the policy’s operational, economic and political aspects. We conclude that the municipalities studied follow a number of patterns regarding population size, location in the southeast part of Brazil, a small number of bus routes, lack of (financial) planning behind FFPT, and predominantly social motivation behind the implementation.