Background: The COVID-19 pandemic placed healthcare design at the heart of the crisis. Hospitals faced challenges such as rapidly increasing their intensive care unit capacity, enabling physical distancing measures, quickly converting to telehealth and telework practices, and above all, keeping patients and staff safe. Improving flexibility in hospital facility design and adaptability of hospital operations to function in “crisis mode” can be seen as ways of future-proofing for pandemics. In a design brief, flexibility is typically mentioned as an important target. Meanwhile, robustness of technical infrastructure is called for, and standardization at unit level with single-occupancy inpatient accommodation may be considered a way to enhance flexibility and adaptability in dealing with a surge in infectious patients. Aim: To future-proof facility design with pandemic preparedness and resilience in mind, this study evaluated what kinds of interventions were taken in Dutch hospital facilities and what perspectives need to be considered when hospitals operate in crisis mode. Methods: We have collected data from facility and estate professionals from 30 Dutch hospitals. Using a practice-based approach, in-depth interviewing helped uncover and compare successful operational strategies and design elements that provided the flexibility needed in the early stages of the recent crisis. Results: As we looked at existing facilities and alterations made to allow hospitals to operate during the COVID-19 pandemic, we discovered that staff availability and adaptability were deemed crucial. Conclusion: We add the perspective of staff as an essential factor to be considered when future-proofing hospital facility desigr crisis mode operation.