It is now well recognized that weekend travel behavior is an important aspect of weekly travel behavior and that several land use types (e.g., shopping, recreation) are associated with congestion during weekends. Moreover, weekend travel tends to be less constrained (due to the absence of regular work and school activities for many individuals) and is therefore likely to show greater variability than weekday travel. Without an understanding of weekend travel behavior, it is difficult to plan for and accommodate the wide variety of activity and travel patterns that occur on weekends. This paper aims to model personal time-space prism constraints associated with weekend travel. Despite the absence of regular work and school activities for many individuals, it is possible that there are household and institutional constraints that influence the action space of individuals on weekends. It is very important to understand and model the time-space prism constraints associated with weekend activity-travel patterns if one is interested in developing robust activity-based microsimulation models of weekend travel demand. In this paper, models of time-space prism vertices are developed for weekend travel behavior using household travel survey data from the 2000 Switzerland Microcensus conducted in Switzerland.