The following research was designed to examine what occurred during a Spanish as a foreign language class taught to a South Korean student, to describe the effect of the implementation of Mobile Learning on the learning process. To this purpose, teaching strategies were designed to develop didactic activities that promoted the use of mobile phones to learn Spanish lexicon. This qualitative case study was carried out at South Korea between December 2019 and April 2020 with the participation of an intermediate level Spanish learner from a telephone conversation program. Resources such as interviews, teaching activities, participant observation were used for the development and collection of information. The results obtained prove that through m-learning the possibilities of time and space for learning are extended to the student thanks to the ubiquitous nature of the mobile, thus conserving the same level of Spanish that was identified at the beginning of the research. Additionally, the opportunity was found to use the WhatsApp application for pedagogical purposes as a tool for transferring class material, assigning activities, keeping track of progress, and making corrections.