Urbanization is one of the most relevant problems facing Latin American countries, where well-planned cities and neighbourhoods remain central to the sustainable development trajectory. Chilean cities face important challenges to improve quality of life in their neighbourhoods and public spaces, necessitating a pragmatic approach to the multiplicity of factors that define sustainability in the built environment. This article evaluates the sustainable potential of built environments in three selected neighbourhoods from three southern Chilean cities through quantitative and qualitative methods, focusing on five key dimensions: density, accessibility, connectivity, diversity, and neighbourhood vitality. Sustainable ranges for these dimensions, identified from the literature, are used as benchmarks for evaluation. Findings reveal that sustainability dimensions interact dynamically rather than functioning independently. For instance, the neighbourhood with the highest population density (155 ppha) also demonstrated high accessibility (0.35) and vitality (71 pedestrians/day), while connectivity (5 intersections/tract) correlated with enhanced public space use. Diversity, with values close to 1 on Simpson's index, was a driver of social interaction and local economic activity. The study highlights the interdependence of these dimensions, showing how accessibility to public spaces and services can foster social interactions. This research provides a methodological framework to assess and guide urban redesign towards sustainability in Latin American cities, with implications for enhancing neighbourhood-level planning and policy-making.