The special issue: Migration Trajectories and Transnational Support Within and Beyond Europe brings together a set of papers with fresh empirical analysis from diverse settings documenting the experiences of migrants residing within and beyond the boundaries of Europe. This introductory article has the objective of laying the groundwork for a better understanding of how migration trajectories are shaped and continued in the contexts of transnational (social) networks and migration control. Firstly, we argue that migration journeys are not necessarily linear and unidirectional movements from origin to destination countries, nor are they clearly demarcated events in time and space. On the contrary, we highlight the dynamic and changing nature of migration trajectories. Secondly, we examine different types of relevant actors who provide support for migrants during their journeys. We focus on transnational social networks and transnationally operating institutions and human smugglers, which influence and facilitate or disrupt migration trajectories. Subsequently, based on the premise that migrants' social networks, expectations, motivations and needs change throughout the migration process, we discuss the ways in which transnational support in a context of migration control relates to the lives of migrants on the move.