This pilot study analysed the learning strategies of advanced students and professional electroacoustic composers engaged in creating new musical pieces through online collaboration. The participants were divided into three groups and interacted in a virtual setting using synchronous (chat and Skype) and asynchronous tools (forum, compositional software) to perform the compositional activities. A multiple case study design was used to describe and interpret the actions of the participants. Forum discussions, Skype dialogues and e-mail exchanges were examined to explore the participants’ interactions and understand their actions during the online activities. Individual semi-structured interviews focusing on the processes and working approaches were conducted. The following themes were considered for the analysis of the collaborative compositional activity: working approach, relational model, leadership, organisation and compositional process. The participants effectively completed the compositional activities on the online platform, and based on the results, the following phases emerged as: (a) context definition; (b) planning/organising; (c) experimenting/generating musical ideas; (d) constructing and (e) evaluating. The findings are discussed regarding the educational implications of developing didactic activities based on collaborative composition.