Online training and international training has been developed so that teachers are prepared to facilitate ESD, they need to develop key sustainability competencies, but in addition to general sustainability competencies, they also need ESD competencies, which can be described as a teacher’s ability to help people develop sustainability competencies through a range of innovative teaching and learning practices. Since there are still many teachers in HEIs who have not yet learned about ESD, there is a need for them to have access to ongoing ESD training. On the one hand, it opens up opportunities to develop the knowledge and skills needed to participate in the sustainable development process. On the other hand, this professional development is a prerequisite for reorienting educational processes and educational institutions. In addition, ESD requires internationalization as an element of teacher education, in particular by holding international debates on ESD and discussions on cultural diversity as...