Kakao Open Chat (OC) is a feature of Kakao Talk. OC is a free, anonymous open board that can be password-protected. One presenter employed English-medium instruction (EMI) with international law classes in the spring and fall of 2022. The spring semester was online-only (asynchronous video lectures), and the fall semester was face-to-face. The classes were large (n = 30-60 per class). In such conditions, students often hesitate to interact. We asked, “Will students use OC to ask for the information they need?” and “Will OC proceed in a safe and positive way?” Surveys were conducted after each semester to assess perceptions of OC, OC chats were downloaded and thematically analyzed, and volunteers were interviewed. Results show that using Kakao OC helps students learn course content and overcome the English barrier, and it contributes positively to learning in both asynchronous and face-to-face conditions. We offer suggestions for its use.