In paediatric clinical care, what is said to a parent or carer as well as when, where, and how it is said, directly advances or diminishes parents' capacities to understand available options and to contribute to decisions about treatment for their child. This makes interprofessional and patient communication an ethical endeavour. Social workers are uniquely situated to observe, participate in, and provide an active link in the communication between families and other health team members. This article reports phenomenological research exploring ethical issues encountered by social workers in their everyday practice communicating with families and other health professionals in a paediatric hospital context in Australia. Data were collected via semi-structured interviews with nine social workers and analysed thematically. Participants described two main communication-based roles: to support families through information provision and to contribute collaboratively to the interprofessional team involved in caring for a child and family. We grouped participants' descriptions of conflict between these roles into five main "communication challenges": (1) holding troublesome knowledge; (2) the need for diplomacy; (3) conciliation; (4) every man and his dog in family meetings; and (5) systems and processes presenting a brick wall. The five communication challenges provide empirically derived examples of how communication occurring within interprofessional health teams and between individual clinicians and parents can act to diminish or enhance parents' experience of care for their hospitalised child. Identifying these challenges may help to inform how communication within interprofessional teams and between clinicians and patients can benefit children and their parents.