This study aims to explore the development of teachers' competences when trained in virtual collaboration. In order to do so, we analyse the data gathered from a group of nine in-service teachers who were trained in a forum and a wiki to become future telecollaborative teachers (TTs). During the course, participants worked in small groups and they had to carry out a series of tasks that included reviewing articles on virtual collaboration and implementing a hypothetical exchange. Quantitative and qualitative analyses were performed on the content from the forum, wiki pages and answers to an end-of-course questionnaire. Findings suggest that there is a relationship between successful collaboration and the development of the knowledge base and competences required by the TT. Therefore, ensuring that sufficient quality interaction takes place among group members is essential in order to encourage the emergence of sound and friendly relationships that will facilitate active participation and negotiation of meaning.