Poor interdisciplinary team communication is a known barrier to increasing inpatient mobility. Understanding why and how clinicians from different disciplines communicate about mobility would help inform communication improvements. This qualitative interview study aimed to describe and explore clinician perceptions about written mobility communication, and perceived barriers and enablers to this communication. A rapid deductive qualitative approach was used to efficiently capture information for local improvement. Clinicians (physical therapists, nurses, physicians, and occupational therapists) working on 3 internal medicine wards in a metropolitan teaching hospital in Brisbane, Australia were purposefully sampled and invited to participate in individual interviews. Questions were based on the Consolidated Framework for Implementation Research. Interviews were recorded, transcribed, and analyzed using deductive and inductive thematic methods. From 17 interviews, key themes identified that written communication about patient mobility is important and valued by clinicians; clinicians learn documentation on the job, often from physical therapists; clinicians are not aware of organizational responsibility for mobility communication; multiple purposes for written communication contribute to multiple locations and inconsistency; and clinicians perceive that improvement would require a multi-disciplinary and multi-level approach. Suggestions for improvement included use of a common language, consistent use of existing bedside communication tools, and clearer responsibility for written communication about mobility. Written communication about patient mobility was valued by clinicians and a range of barriers to effective interdisciplinary communication identified. Clear professional roles and responsibility for written mobility communication is important. Suggestions for improvement included an interdisciplinary language supported by multi-disciplinary education and organizational governance. Written communication about patient mobility is recognized as critical to safe, high-quality hospital care. Our findings suggest that successful mobility communication improvements must involve multiple disciplines and include clear organizational governance to support staff training, clear role responsibilities, and quality monitoring.