Education in implementation science, which involves the training of health professionals in how to implement evidence-based findings into health practice systematically, has become a highly relevant topic in health sciences education. The present study advances education in implementation science by compiling a competence profile for implementation practice and research and by exploring implementation experts' sources of expertise. The competence profile is theoretically based on educational psychology, which implies the definition of improvable and teachable competences. In an online-survey, an international, multidisciplinary sample of 82 implementation experts named competences that they considered most helpful for conducting implementation practice and implementation research. For these competences, they also indicated whether they had acquired them in their professional education, additional training, or by self-study and on-the-job experience. Data were analyzed using a mixed-methods approach that combined qualitative content analyses with descriptive statistics. The participants deemed collaboration knowledge and skills most helpful for implementation practice. For implementation research, they named research methodology knowledge and skills as the most important ones. The participants had acquired most of the competences that they found helpful for implementation practice in self-study or by on-the-job experience. However, participants had learned most of their competences for implementation research in their professional education. The present results inform education and training activities in implementation science and serve as a starting point for a fluid set of interdisciplinary implementation science competences that will be updated continuously. Implications for curriculum development and the design of educational activities are discussed.