Objective. To explore the health professionals' (HPs) perceptions and experiences of advance care directives (ACDs) and advance care planning in Australian palliative care services.Methods. A nationwide survey of 105 palliative care services was conducted, with two HPs from each service invited to participate. A qualitative analysis of open responses about advance care planning was undertaken.Results. Sixty questionnaires were returned with open responses. Most responders were nurses (75%), aged 40 years (80%) and with a mean of 12 years palliative care experience. Data were grouped into four key themes: (1) the ACD; (2) the process of developing ACDs; (3) the process of using ACDs; and (4) the consequences of having ACDs. Participants were positive about advance care planning, commenting that ongoing communication about end-of-life care ensures mutual understanding between patients, family and HPs. Provision of care was considered easier and more efficient with an ACD in place. ACDs were perceived to reduce distrust and conflict between family, friends and HPs, and promote communication. Suboptimal documentation, clarity and explicitness limited the usefulness of ACDs when they were available.Conclusions. Advance care planning benefits HPs, patients and their family. To maximise these benefits, ACDs need to be clear, comprehensive, medically relevant and transportable documents.What is known about the topic? Ideally, advance care planning encompasses the identification and documentation of a person's preferences for future medical treatments and care in preparation for an occasion when the person cannot express their values and wishes. The uptake and practice of advance care planning is inconsistent, and the extent to which it is used by health professionals and patients is variable. Many people are cared for at the end of life in specialist palliative care services, but the intersection between palliative care and advance care planning remains under-researched. What does this paper adds? ACDs facilitate communication and advance care planning; help establish trust between health professionals, patients and their families; and make multiple aspects of care easier for HPs. Processes surrounding ACDs, particularly inadequate documentation, limit adherence and application. What are the implications for practitioners? Clear communication is necessary for effective ACD development and application. The presence of an ACD makes communication and advance care planning easier, and improves trust between HPs, patients and their family. To be useful, ACDs must be clear, comprehensive, medically relevant, transportable documents.