After the Costa Rican government signed a commitment to implement the UN Decade of Education for Sustainable Development (DESD), the challenge was how to put the commitment into action. Fortunately, an opportunity presented itself with an initiative called Peace with Nature (Iniciativa Paz con la Naturaleza-IPN), under which a teacher training course called Education for Sustainable Development Regional Course (CREADS) was implemented. A "coalition" of governmental and nongovernmental organisations, coordinated by the Ministry of Education and IPN, was put in place to deliver the course and it was decided to use the Earth Charter as the course framework. This article describes the process of creating this course, its content and methodology, and analyses the course impact, lessons learned and challenges ahead. (Contains 5 tables and 3 notes.)