TPACK is a theory that combines three basic knowledge, they are Technological Knowledge (TK), Pedagogical Knowledge (PK) and Content Knowledge (CK). Perception in this study divided into four indicators such as teachers' knowledge, teachers’ emotion, teachers’ behavior and teachers’ motivation. Therefore, this study investigated how the EFL teachers implemented TPACK and their perception on the use of online learning applications at Fastabiqul Khairat Senior High School Samarinda. A case study was applied in this study with two participants selected purposively through judgmental sampling. This study was mainly guided by using interview protocol and observation guidelines. The data was analyzed through preparing and organizing the data, exploring and coding the data, coding to generate the descriptions and themes, representing and reporting qualitative findings, interpret the findings, validating the finding accuracy. The results revealed that the way how EFL teachers implemented TPACK is both participants used Cambridge One, Google Classroom and WhatsApp group as online learning applications or technologies (TK) to support the student-centered, discovery learning, problem-based learning, demonstration, expository and discussion as their pedagogy (PK) to taught about recount text and adjectives as their content (CK). Both EFL teachers had positive perceptions about the online learning applications they used to teach EFL, they were satisfied with the benefits provided by the online learning applications they used, they believed that the teaching methods they implemented are appropriate to the technology they used and the content they taught and they felt that they have a great desire to master all the features of the online learning applications they used to teach EFL. The behavior pattern of both participants in improving their professional competence despite the challenges faced is by making various efforts such as providing good role models, instilling religious attitudes, improving EFL education learning using advanced technology and improving literacy and discussion skills in order to create the desired educational environment.