Communicative language teaching (CLT) has become the favourite teaching approach of many English teachers because of its focus on communication (Kumaravadivelu, 2006). A number of researchers have investigated EFL teachers' perceptions and implementation of CLT in Saudi tertiary level education. Some researchers reported on how CELTA training affects EFL teachers' perceptions and implementation of CLT. However, there is a gap in the literature with regard to the lived experiences of how non-native English speaker teachers (NNESTs) who do or do not have a CELTA qualification understand and apply CLT in Saudi tertiary level EFL education. Therefore, this mixed-methods ethnographic research focuses on filling this gap. Data were collected through three research tools, namely a survey, vignettes and classroom observations. All the participants were teaching EFL at the Saudi tertiary level. Twenty-six CELTA holders and forty-four non-CELTA holders participated in the survey about their perceptions and implementation of CLT. Four CELTA holders and three non-CELTA holders wrote a number of vignettes on how they conceptualize and apply CLT. Classroom observations were conducted for two CELTA holders and two non-CELTA holders. The statistical survey data were analysed using SPSS, and the vignettes and classroom observations were examined thematically. The findings revealed that both CELTA and non-CELTA holders have a reasonable understanding of CLT. However, they also showed that the teachers only implement CLT to some extent, suggesting that more training on applying communicative activities and group- and pairwork is needed in EFL classrooms.