This article presents an original and innovative way for primary teacher training concerning teaching the 17 Sustainable Development Goals (SDGs) using concept maps. Four types of concept maps were designed and built so that the interconnections between the 17 SDGs could be captured and the complexity of their interdependencies could be highlighted. This educational tool was used in 14 workshops with interesting results, which took place in Piraeus (Greece), and was addressed to primary teachers. Concept maps have proven to be a powerful tool for highlighting correlations between the 17 SDGs, as each group of teachers who used them linked the SDGs in a unique manner and simultaneously justified this interconnection. In addition, the use of concept maps was an opportunity for teachers to experience group work and its quality characteristics, such as participation, exchange of opinions, argumentation and different perspectives.