Semi-immersive visualization facilities support research, planning, and decision-making at the science-society-policy interface. Decision theaters, visualization studios, and similar installations—here referred to as Decision-Visualization Environments (DVEs)—facilitate human-computer-content interactions to explore climate change impacts, resource management practices, and urban design solutions. This comparative study analyzes the current practices of seven DVE facilities from around the world based on expert interviews, site visits, and document review. We found common practices across 53 attributes concerning the planning, stakeholder involvement, and realization of DVE activities. DVEs need good facilitation and purposeful combination to unlock their full potential. An active network of DVEs could constitute a productive learning community to pool and coordinate activities and share insights. Based on our findings, we deduce recommendations on how to improve the design of existing DVEs, to create new DVEs, as well as to plan DVE projects and events.