Informal learning communities in which participants show critically reflective work behaviour (CRWB) have the potential to support lifelong learning. In practice this behaviour does not always occur in groups of autonomous professionals. This study explores design principles (DPs) that could act as social affordances for CRWB, within the context of healthcare professionals. From the literature, 28 DPs were deduced. In an online Delphi study, 12 experts gave their opinions about these. To explore strategies for implementation of these DPs, a face-to-face expert discussion meeting was organized. The Delphi study resulted in a subset of 13 DPs considered to be relevant for CRWB. Some of the design principles were confirmed or reformulated, others were considered to be unimportant. Exploration of strategies for implementation confirmed the importance of having moderators from within the group. The results of this study, combining issues of design and implementation, could contribute to the discussion about the support and set-up of learning communities for autonomous professionals. A framework for behavioural change is considered that could help to understand why these DPs should influence participants' interaction.