Early mobilization and rehabilitation, multidisciplinary stroke expertise and comprehensive therapies are fundamental in a stroke unit. To achieve effective and safe stroke care, the physical environment in modern stroke units should facilitate the delivery of evidence-based care. Therefore, the purpose of this study was to explore patients’ activities and interactions in a stroke unit before the reconstruction of the physical environment, while in a temporary location and after reconstruction. This case study examined a stroke unit as an integrated whole. The data were collected using a behavioral mapping technique at three different time points: in the original unit, in the temporary unit and in the new unit. A total of 59 patients were included. The analysis included field notes from observations of the physical environment and examples from planning and design documents. The findings indicated that in the new unit, the patients spent more time in their rooms, were less active, and had fewer interactions with staff and family than the patients in the original unit. The reconstruction involved a change from a primarily multi-bed room design to single-room accommodations. In the new unit, the patients’ lounge was located in a far corner of the unit with a smaller entrance than the patients’ lounge in the old unit, which was located at the end of a corridor with a noticeable entrance. Changes in the design of the stroke unit may have influenced the patients’ activities and interactions. This study raises the question of how the physical environment should be designed in the future to facilitate the delivery of health care and improve outcomes for stroke patients. This research is based on a case study, and although the results should be interpreted with caution, we strongly recommend that environmental considerations be included in future stroke guidelines.