This study investigates pragmatic development in the English-medium instruction (EMI) setting of the Valencian Community in Spain. More specifically, the study examines whether the intensity of EMI influences functional adequacy (FA) in second language (L2) writing. Participants were 102 EMI learners, each of whom wrote three motivation letters over one academic year in English. The rating scales designed by Kuiken and Vedder (2017) were used to examine the FA of the written texts in terms of cohesion, coherence, task requirements, content, and comprehensibility. Quantitative results revealed significant differences among the EMI groups under analysis, suggesting that the intensity of instruction may exert an influence on FA in L2 writing. Results from this study show the importance of intensity of exposure to EMI for L2 writing.