The European Union funded LITERALIA project connected adult language learners from four countries with the help of an online workspace and supported visits. The project was based on Tandem principles, whereby learners of different languages support one another in learning one another's language and culture, in turn taking on the roles of learners and expert informants. This article analyses project participants' intercultural learning and shows their development of intercultural maturity online. Qualitative data collected through observation, feedback and interviews are analysed and used to present a description of adults' experiences in intercultural learning. The study focuses on adult learning, drawing in particular on Mezirow's concept of "perspective transformation" (Mezirow, 1981), a concept applied to intercultural experiences by Taylor (1994). Three different models of intercultural learning--all of them multidimensional and multifaceted--have influenced our research: (a) intercultural competency (Taylor, 1994); (b) intercultural communicative competence (Byram, 1997); and (c) intercultural maturity (King & Baxter Magolda, 2005). However, few studies have been conducted in this area that integrate online interaction in non-formal learning settings as our study attempts. (Contains 2 figures and 12 notes.)