Various hybrid working scenarios have become increasingly popular but there is limited knowledge of their effect on knowledge sharing in organizations. The purpose of this research is to investigate the effect of the extent of unplanned social interactions on solicited knowledge sharing in five working scenarios. We adopted an agent-based modeling approach and simulated individual knowledge-related behaviors in an SME-sized office. Simulation results show that knowledge sharing between agents is related to the frequency of unplanned social interactions between them and that synchronized office-presence days play an important role. In addition, we saw that, when knowledge from co-workers is less accessible, the use of information and knowledge repositories increases. These results lead us to conclude that an organization’s knowledge management system should take into account individuals’ working modes.