There is a consensus in language learning and teaching that the concept of authenticity in the classroom is beneficial to the learning process. This phenomenology case study explored 31 EFL high school students' perceptions about the authenticity of using English as the language of instruction during synchronic lessons with U.S. teachers. Data was collected from two synchronous interactive lessons and students' open-ended reflections. A thematic content analysis was adopted to examine themes on perception, motivation, and participation. The findings revealed students' insights into their learning experiences through synchronous interactions with teachers, highlighting how authentic learning gave them opportunities to practice communication strategies and learn vocabulary incidentally. This study provides pedagogical implications for integrating authenticity in foreign language classrooms.