ABSTRACT This article explores how boundary salience affects the stability of intergroup contact. The research draws on interviews with 57 residents of Cerco and Pasteleira, two residential areas in Porto (Portugal), which are characterized by administrative, socioeconomic, and ethnic differences. The interviews reveal that, despite their proximity to out-groups and their spaces, some residents avoid contact opportunities to achieve separateness, while others enter into voluntary and involuntary contact. Such individual practices reflect subjective interpretations of boundary salience. The study finds that boundary salience affects the stability of intergroup contact by influencing individuals’ socio-spatial practices. These practices are the most stable and consensual at the extreme poles of boundary salience (i.e. very salient and very blurred), which result in stable forms of either segregation or integration. However, when the salience of boundaries is moderate, individual practices are more inconsistent and sensitive to subjective interpretations and personal experiences, often resulting in fluctuating forms of social mixing.