The current study aimed at investigating how mobile seamless technology can be used to enhance the pragmatic competence of learners of Chinese as a second language (CSL). 34 overseas CSL learners participated in this study. They were randomly assigned into two groups: the classroom group, executing language tasks in fake contexts in a traditional classroom; and the real-world group, executing identical tasks in real world with the support provided by a mobile seamless learning platform (MOSE). All the CSL learners were asked to make a plan of receiving a friend abroad after collecting the information about the shops or stores in the neighborhood of the campus. Both quantitative (Mandarin communication performance test) and qualitative data (videos recorded during the learning process) were collected and analyzed in this 4-week study. The analytical results show that both groups made significant improvements in the test-based Mandarin communication performance. However, according to the qualitative data, the CSL learners in the real-world group made significantly fewer errors when executing language tasks than did those in the classroom group. Furthermore, they did not depend on their first language to communicate with the people they visited in the real world and they had more peer cooperation with the support provided by the MOSE platform compared with those in the classroom group.