Despite evidence suggesting that neighbourhood characteristics are associated with physical activity, very few mixed methods studies investigate how relocating neighbourhood, and subsequent changes in the built environment, influences physical activity. This sequential mixed methods study estimates associations between changes in overall physical activity and transportation walking and cycling and changes in objectively assessed neighbourhood walkability (quantitative phase) and describes perceived barriers and facilitators to physical activity following residential relocation (qualitative phase). During the quantitative phase, self-reported changes in transportation walking, transportation cycling, and overall physical activity following residential relocation were measured using a 5-point scale: (1) a lot less now, (2) a little less now, (3) about the same, (4) a little more now, and (5) a lot more now. Walkability improvers reported a slight increase in transportation walking (mean = 3.29, standard deviation (SD) = 0.87), while walkability decliners reported little or no perceived change in their transportation walking after relocation (mean = 2.96, SD = 1.12). This difference approached statistical significance (p=0.053). Furthermore, walkability decliners reported a slight decrease in transportation cycling (mean = 2.69, SD = 0.96), while walkability improvers reported little or no perceived change in their transportation cycling after relocation (mean = 3.02, SD = 0.84). This difference was statistically significant (p<0.05). Change in walkability resulting from relocation was not significantly associated with perceived change in overall physical activity. Our qualitative findings suggest that moving to a neighbourhood with safe paths connecting to nearby destinations can facilitate transportation walking and cycling. Some participants describe adjusting their leisure physical activity to compensate for changes in transportation walking and cycling. Strong contributors to neighbourhood leisure physical activity included the presence of aesthetic features and availability of recreational opportunities that allow for the creation of social connections with community and family.