We use a longitudinal examination of the production of a complex vessel to develop theory concerning operational flexibility behaviors within interorganizational projects. We find that operational flexibility behaviors are enabled by trust between project participants, sense of urgency, and the availability of resources. These enablers are in turn positively influenced by positive experiences in previous interactions (“shadow of the past”) and expectations of possible future collaboration (“shadow of the future”), the temporary nature of interorganizational projects and slack in project tasks, respectively. The positive effect of enablers on operational flexibility is weakened by the time pressure project participants experience. The latter is also caused by the temporariness of interorganizational projects. Based on our findings, we propose that the different time dimensions play a crucial role in explaining flexibility behaviors in interorganizational projects: the temporariness that is an essential characteristic of interorganizational projects has two potentially opposite effects on the behavior of its participants, and we argue that shadows of the past and future play a decisive role in which of the two effects will dominate. The theoretical framework based on our case study suggests that the temporariness of interorganizational projects is indeed important—as acknowledged in the literature—but that its effect is contingent on shadows of past and future.