<p>Despite the growing importance of long-term care due to an aging global population, few studies have addressed information-sharing challenges in the transition of older adults between hospitals and care facilities. To address these challenges, we conducted a mixed-methods study involving staff from both facilities in Japan. Three investigations were undertaken to identify the challenges of information sharing, revealing the absence of appropriate sharing methods, the failure to share information beyond current medical information, and the need to share certain information orally. Moreover, because of their different natures and roles, hospitals and care facilities consider other types of information important. These findings will contribute to research on aging issues and support for older adults, as a lesson learned from the most aging society.</p>