This prospective longitudinal study aimed to assess the sustainable effect on patients' assessment of ward atmosphere and quality of care at three forensic psychiatric clinics relocated to new facilities built with the latest evidence-based healthcare environment design to support recovery. Baseline data were collected in the old facilities and during three follow-ups after relocation, between 2010 and 2016. Of 74 patients who gave informed consent to participate, 58 patients (100%) answered the questionnaires at baseline, with 25 patients (43%) completing them at Follow-up 1, 11 patients (19%) at Follow-up 2, and seven patients (12%) at Follow-up 3. This study provides evidence that the mean values of patients' perceptions of care quality in these forensic psychiatric facilities increased when moving to new buildings and were stable up to 3 years after relocation, which was statistically significant in the domain of secluded environment (p < 0.05). The sample size at Follow-up 3 was small, and thus the results are limited, which indicates that further research is needed to confirm the findings.