This chapter has a particular focus on the observers’ role in simulation-based learning activities. Simulation-based learning is often organised so that participants rotates between active participation in the scenario and participation as observers. The research examples provided show that the conditions for learning are related to the locations where and the ways the observers are situated, and to how the instructions to the observers are formulated. Arguments are put forward that the observers’ role in simulation has unexploited potential for developing skills of noticing.