Interactive and communicative situations within social environments are prerequisites for learning in collaboration. Synchronous communication offers the opportunity to actively engage students in collaborative learning activities. This paper is based on an action research conducted within a learning project including synchronous communication between students in lower secondary school. The students collaborate in a cross-border project involving Danish, Norwegian and Swedish students. The aim of the paper is to analyse the conditions for participation in synchronous online learning. collaborative learning. The findings are derived from the empirical study within a three-part learning project using synchronous online communication. The conclusion is that the conditions for participation in synchronous online learning are authenticity, motivation, confidence, preparation and teacher engagement.