Education for Sustainable Development (ESD) is a core element of UNESCO’s Sustainable Development Goal (SDGs) Target 4.7, which seeks to ensure that all learners acquire the knowledge and skills needed to promote sustainable development through education for sustainable development. The German Federal Ministry for Education and Research (BMBF) followed suit in 2015 and launched a high scale national monitoring of the current state of ESD implementation. In this context, suitable ESD indicators should be analyzed to inform policy and research agendas. The present project is part of the national monitoring within Germany’s Global Action Program (GAP) actions. The research team at the University of Education in Freiburg conducted a study to evaluate the accessibility of data and the measurability of ESD-relevant teacher training (TT). During the two-step procedure for data collection on ESD-relevant TTs in Germany, an extensive list of ESD related search terms first captured 66,935 TTs with possible ESD relevance in the evaluation period. Second, the collected data was analyzed using Mayring’s qualitative content analysis. The 66,935 TTs were thereby reduced to 3818 TTs with different degrees of ESD relevance. The results of the evaluation study show that suitable ESD indicators, the FESD (formula for the ESD-indicator for TTs) (basic), FESD (basic, rated) and FESD (pro), could be developed and calculated for 15 of 16 federal states in Germany. The gathered insights show a path towards ESD monitoring in TT to clarify the needs and achievements of ESD implementation in the field of continuing education of teachers. However, the presented indicators only show a possible path for ESD indicator development. A comprehensive set of ESD indicators should also focus on the micro or output (e.g., ESD competencies) level. These insights for the future seem worth striving for not only in Germany or on the national level but also internationally to foster ESD, Target 4.7 of the SDGs and the SDGs in general.