Construction managers are the drivers of project success. To perform well, they need to possess key competencies, such as knowledge, skills, and attitudes, all of which can be improved through proper training. However, despite the skill shortage that still exists in the construction industry, extant literature does not precisely reveal the training methods and training approaches that can impart to construction managers the knowledge, skills, and attitudes they require. Therefore, the aim of this study was to identify training methods and training approaches that can develop the knowledge, skills, and attitudes that construction managers require. The paper presents the results of a Delphi study with 12 experts and 44 professionals, who were asked to provide their opinions on training methods and training approaches that can be adopted to develop the core competencies expected of construction managers. The study revealed 20 elements of knowledge, skills, and attitudes that are most significant to construction managers in the form of competencies and the training methods and training approaches that can deliver those competencies. The most significant knowledge was found to be schedule management and planning, the most significant skill time management and the most significant attitude supportive leadership. Furthermore, learning by doing and private training provided within the workplace were identified as the most favourable training methods and training approaches, respectively for construction managers to acquire the significant competencies they require.