This article aims to study the impact that networks of contacts and circles of musicians have in generating work opportunities within the musical field of jazz. The research has been framed within the perspective of Pierre Bourdieu's artistic field (1984, 1987) and the main characteristics of conformation of collaborative circles studied by Michael P. Farrell (2003). The methodology used is qualitative and is based on semi-structured interviews and participant observation conducted between 2015 and 2016 with musicians from the jazz scene of the city of Barcelona. From this fieldwork, we have analyzed the main contributions that contact networks and collaborative circles of jazz musicians offer to generate work opportunities within the musical artistic field. We have also studied how the collective work and the conformation of musical groups become a crucial artistic and creative platform both for the development of the individual careers of musicians and in the field of joint exploration of the musical language itself.