While there is a substantial body of research on the health implications of walking, the physical, emotional and social outcomes of walking have received limited attention. This paper explores the wellbeing effects of walking and how the walking environment fosters or hinders such wellbeing effects. This is done using a novel mobile data collection technique, allowing for in situ recording of walking experiences, combined with focus groups. The results of the study suggest that the affect level of pedestrians is highest in places with many activities going on and many people being around. However, in support of restoration theory, we find that places with lower activation levels may also foster positive feelings, especially if they contain natural elements (such as trees and water) or buildings with a more contemplative character. While perceived safety of walking locations does not directly increase the affect level, it makes people feel more active, probably because it increases people's autonomy and self-esteem.