Neighbourhood-based research on the rise of super-diverse cities has mostly focused on the implications of living in super-diverse neighbourhoods for individual relations, and paid little attention to processes of group formation. This paper focuses on how residents of superdiverse neighbourhoods identify social groups. Drawing on the concept of symbolic boundary making, it provides insights into how residents draw, enact and experience boundaries. Using the results of in-depth interviews with residents in Antwerp and Rotterdam, we show that superdiversity complexifies but does not counteract group formation. Residents draw multiple, interrelated symbolic boundaries along ethnic, class and religious lines and lines based on length of residence, which are sometimes used interchangeably. We also show that group boundaries are dynamic and constantly (re-)created. Finally, we show that discursive boundaries do not necessarily lead to less social contact across these boundaries, thus illustrating that symbolic boundaries do not always result in segregated social patterns.