The myriad of possibilities brought about by the advent of Web 2.0 in terms of communication and interaction have revolutionised educational practices over the past few years. One of the most promising educational approaches resulting from this revolution is online intercultural exchange or telecollaboration, which has been reported to contribute towards the development of 21st century competences. Many of the benefits of online intercultural exchange have been extensively explored in the literature and numerous studies have been carried out. However, very few studies have looked into the differences between an L1 or mother tongue exchange and an L2 or lingua franca exchange as far as the development of 21st century competences is concerned. This paper aims at filling this gap by exploring and comparing the results of two configurations of Online Intercultural Exchange carried out over a period of 4 months with 125 participants. The results indicate that the L1 exchange was perceived as more beneficial than the L2 exchange for most of the competences studied (linguistic and communicative competences, Language for Specific Purposes learning, learner autonomy and teamwork). Meanwhile, the L2 exchange was considered as more beneficial for the development of intercultural competence. Furthermore, no significant differences were observed regarding digital literacy.