This small scale study aimed at identifying (1) the characteristics of teaching practices in CLT classrooms, (2) teachers' opinions underlying such practices, (3) their positions while adopting CLT, and (4) a knowledge base used as a framework of CLT implementation. Eight Thai teachers who regarded themselves as CLT proponents voluntarily took part in this study. Data collected via classroom observations and post-teaching semi-structured interviews indicated that CLT involved four common features including promoting 'small talk' in the target language, beginning the lesson with the combination of lead-in and presentation strategies, positively reacting to students' linguistic errors, and emphasizing semi-communicative activities. The participants' opinions underlying CLT implementation centered on playing multiple roles including lesson designers, class managers, and English users with certain levels of English proficiency. Content, pedagogical content, and subject matter knowledge served as their major elements of the knowledge base for teaching when conducting CLT lessons.