This study sought to investigate the impact of using Cambly, a computer-mediated communication tool, on the speaking proficiency of English as a foreign language (EFL) learners. Further, it aimed to explore the participants' perceptions of using Cambly. The study employed an experimental design featuring a mixed-methods approach to data collection that involved pre- and post-testing of the participants' speaking proficiency as well as semi-structured face-to-face interviews. The study sample consisted of 28 EFL university students who were divided into the control and experimental groups. The participants in the experimental group used Cambly to conduct audio calls with native speakers of English over a period of 4 weeks. The quantitative analysis of the participants' speaking proficiency tests revealed no significant differences between the experimental and control groups' post-test scores. Moreover, no significant differences were found between the experimental group's pre- and post-test scores. The qualitative analysis of the participants' interviews revealed that the use of Cambly had a positive influence on their speaking proficiency, motivation, anxiety level, speaking opportunities, autonomy, social relationships, and cultural awareness.