The design of urban environments has the potential to enhance the health and well-being of residents by impacting social determinants of health including access to public transport, green space and local amenities. Commencing in 2003, RESIDE is a longitudinal natural experiment examining the impact of urban planning on active living in metropolitan Perth, Western Australia. Participants building homes in new housing developments were surveyed before relocation (n = 1813; 34·6% recruitment rate); and approximately 12 months later (n = 1437). Changes in perceived and objective neighbourhood characteristics associated with walking following relocation were examined, adjusted for changes in demographic, intrapersonal, interpersonal and baseline reasons for residential location choice. Self-reported walking was measured using the Neighbourhood Physical Activity Questionnaire. Following relocation, transport-related walking declined overall (p < 0.001) and recreational walking increased (p < 0.001): access to transport- and recreational destinations changed in similar directions. However, in those with increased access to destinations, transport-related walking increased by 5.8 min/week for each type of transport-related destination that increased (p = 0.045); and recreational walking by 17.6 min/week for each type of recreational destination that increased (p = 0.070). The association between the built environment and recreational walking was partially mediated by changes in perceived neighbourhood attractiveness: when changes in ‘enjoyment’ and ‘attitude’ towards local walking were removed from the multivariate model, recreational walking returned to 20.1 min/week (p = 0.040) for each type of recreational destination that increased. This study provides longitudinal evidence that both transport and recreational-walking behaviours respond to changes in the availability and diversity of local transport- and recreational destinations, and demonstrates the potential of local infrastructure to support health-enhancing behaviours. As neighbourhoods evolve, longer-term follow-up is required to fully capture changes that occur, and the impact on residents. The potential for using policies, incentives and infrastructure levies to enable the early introduction of recreational and transport-related facilities into new housing developments warrants further investigation.