The integration of external staff into a hospital’s disaster response can present technical challenges. Although hospitals will always prefer to use their own staff in disaster response, there have been many historical examples where external staffing is required. During the 2016 Kumamoto Earthquakes, the Oita Prefectural Hospital required medical professionals to expand disaster response staff. They were able to identify 2 appropriate emergency physicians belonging to a remote hospital who had previously worked at the Oita Prefectural hospital. The physicians were effectively able to supplement the hospital staff, providing care for additional patients, and giving the existing on-duty staff some respite. Based on our experience, we suggest that hospital coalitions and disaster response authorities explore mechanisms of cross-credentialing and cross-training staff to make it easier to share staff in a disaster.