In the Netherlands, two new approaches have been developed for acute and forensic psychiatry, called High and Intensive Care (HIC) and Forensic High and Intensive Care (FHIC). The models provide standards for temporary high-quality clinical care for patients in crisis and combine practices to reduce seclusion. To support the implementation of these approaches, Communities of Practice (CoPs) were created, including peer providers, mental health nurses, psychiatrists and managers. CoPs are increasingly used in healthcare. However, CoPs vary greatly in form and objective, and more insight is needed in the organisation and facilitation of CoPs. Therefore, the aim of this study is to gain insight into the lessons learned and perceived effects of the CoPs. A qualitative approach was used. Data were collected through focus groups (n = 3) with participants in the CoPs, feedback meetings with teams implementing HIC (n = 78) or FHIC (n = 23), and observations by the researchers. Data were analysed thematically. Lessons learned are: 1) create an ambassador role for CoP participants, 2) organize concrete activities, 3) take care of a multidisciplinary composition, and 4) foster shared responsibility and work on sustainability. Perceived effects of the CoPs were: 1) support of HIC and FHIC implementation, 2) creation of a national movement, and 3) further development of the HIC and FHIC approaches. The audits served as an important vehicle to activate the CoPs, and stimulated the implementation of HIC and FHIC. The findings may help others in creating a CoP when it comes to the implementation of best practices and improving healthcare.