Education for Sustainable Development (ESD) has been stated as fundamental in regards to achieve the Sustainable Development Goals set by the UN. This exploratory research aims to contribute to getting more knowledge about how promoting and strengthening ESD in the secondary school level, particularly, through the role of teachers and the way they can be engaged, prepared and supported to deliver knowledge and experiences for effective learning experiences of their students. Specifically, this study explores the benefits of collaboration between teachers within networks in relation to ESD and its limits. Using the lens of Teaching Communities (TC) which considers the theories of Communities op Practice (CoP) and teachers Professional Learning Communities (PLC) for analyzing the data collected. Also, the opportunities of Information and Communication Technologies (ICT) in this field as spaces that help in enabling collaboration are considered. The research is conducted by taking the case of the NGO Eco-Schools which provides a global program for ESD but has not formal learning communities. 10 teachers and 2 National Operators of Eco-schools were interviewed, and the main concepts mentioned were analyzed. The findings showed similarity with the characteristics and conditions of the theories used. However, the exploratory purpose of this research doesn’t have statistical validity, therefore, further research is required. Although, information and communication technology provide valuable insights for developing quantitative tools.