The focus of this research is to examine the role of student-teacher interaction during swimming lessons. Forty-nine (49) elementary school PE teachers, swimming trainers and instructors (28 females, 21 males) consented to participate in this study. A total of seventy-seven (77) swimming lessons were videotaped and coded with the Cheffers' Adaptation of Flanders Interaction Analysis System (CAFIAS). Altogether 177.434 tri-seconds were observed. In the lessons teacher's observation were most prevalent (31, 11%), teacher's explanation (19, 29%) and organization (13, 52%) seemed also notable. Students spend most of the swimming lessons with motor-related activities (77%). It is important to state that teachers who teach swimming develop a high level of non-verbal activity. From the analyses of the data, it can conclude that in this special area of teaching, the teacher-student interactions and communications that evolve are content specific and so different from those evolving in classrooms or PE lessons. (Contains 8 tables and 2 figures.)