Background Observational work to develop the ACCCN Competency Standards was undertaken more than 20 years ago. Since then the landscape of critical care nursing as a specialty has changed and it is not known if the Competency Standards reflected contemporary practice. Objectives To revise the ACCCN Competency Standards for Specialist Critical Care Nurses to ensure they continue to meet the needs of critical care nurses and reflect current practice. Methods A two-phased project was undertaken. In Phase I focus groups were held in all states. Thematic analysis was conducted using two techniques. The standards were revised based on the main themes. Phase II consisted of an eDelphi technique. A national panel of critical care nurses responded to three survey rounds using a 7 point likert-type scale to indicate their level of agreement with the revised standards. A 70% agreement level for each statement was determined a priori. Results Phase I: 12 focus groups (79 participants) were conducted. Phase II: A panel of specialist critical care nurses (research, management, clinical practice and education) responded to round 1 (n = 64), round 2 (n = 56), and round 3 (n = 40). Fifteen practice standards with elements and performance criteria were grouped into four domains (professional practice, provision and coordination of care, critical thinking and analysis, collaboration and leadership). The revised Practice Standards for Specialist Critical Care Nurses build upon and are additional to the Nursing & Midwifery Board of Australia National Competency Standards for Registered Nurses. The standards reflect contemporary critical care nurse practices using an expanded range of technologies to care for complex critically ill patients across the lifespan in diverse settings. Conclusion The national study has resulted in the 3rd edition of the Practice Standards for Specialist Critical Care Nurses. There was input from stakeholders and agreement that the revised standards capture contemporary Australian critical care nursing practice.