This paper reports on the process of designing an Oral Communication Skills course offered in the first year of an undergraduate English Language Teaching program offered at an English-medium university in Turkey. This course was designed for pre-service teachers of English as a foreign language, considering the environmental factors and needs employing Nation and Macalister's (2010) "Mercedes model" of curriculum design. Course instructors, freshman pre-service teachers, and recent graduates of the program participated in the study. Principles used in course design are guided by the literature and by the results of environment and needs analyses. Taking the interests of students into consideration in topic selection, researchers adopted the theme-based approach. A course matrix was developed incorporating the Six Ts approach, with an aim to address communicative, interactional, and intercultural competence by engaging all students in meaningful interaction across various settings and speech events. This study stands as an example of how diverging constraints can be accommodated in a theme-based approach to course design, responding to the needs and expectations of the learners.