When organising TeleCollaboration (TC) encounters at primary or secondary schools, especially technological and organisational complexity, alongside pedagogical issues, plays an essential role in the degree of success of the exchanges. Within the European TeCoLa project, pilot experiences have been organised using innovative but 'simple' technologies, like Padlet or Voki to more demanding and complex ones like 3D virtual worlds in OpenSim. The present paper presents the experiences of three pilot exchanges differing in complexity and reports on learners' experiences.[For the complete proceedings, see ED600837.]