Incidental learning is a human learning paradigm that takes its form as a response to unplanned initiatives, potentially occurring at any time and at any place. It is emerging as very promising in the case of learning a second language, as it multiplies the occurrence of unexpected and unintentional learning situations. Still open, and subject of debate, is the issue of which is the right methodology to be applied when mobile computer-based technologies are exploited to provide support to such kind of a learning paradigm. Drawing on the results of an international Project (ILOCALAPP), in this paper we provide our reflections on a specific incidental learning methodology we have adopted, based on the use of a mobile application (the UniOn! App) that was developed at the University of Bologna to support mobility students in their daily activities. Our main goal was to understand if such an approach was effective to let individuals incidentally learn the Italian language and culture driven by our mobile application, while conducting informal and daily activities. Specifically, we aimed to measure how much students have learned Italian, by means of self-evaluation and self-assessment tools and statistical analysis, involving 95 students who incidentally improve their Italian language skills, supported by the app. In particular, we adopted a quasi-experimental design, and we focused our investigation on four different dimensions: target users, users’ language background, duration and frequency of use, context of use. The 95 participants were grouped into 5 case studies, based on the four different dimensions. After having used the app, the participants were asked to answer a survey. The obtained results confirm the viability of our approach, showing that incidental learning is enhanced if certain conditions (i.e., integrated guidance) are met, where more than 55% of the participants reported to be more confident about their acquired skills.