This study aims to explain how EMI is implemented in a bilingual program. The researcher also focuses on the challenges, benefits and implications from the perspective of students and teachers. This research uses a descriptive qualitative method. Data were collected using observation and in-depth interviews with 15 participants from bilingual class 8B at SMPI Al Azhar 23 Semarang, categorized into 3 levels: low, middle and fast. The findings show that the main challenges in implementing English as Medium Instruction (EMI) in a bilingual environment include unfamiliar vocabulary, low language proficiency and teacher unpreparedness, which hinder students' understanding. In addition, incorrect pronunciation by teachers leads to student confusion and passive learning. On the other hand, teachers have difficulty explaining the material due to their non-English educational background. However, teachers and students benefited from enhanced English language skills and self-confidence, although students felt shy when speaking in public. Therefore, schools should enhance support for bilingual students through appropriate resources and programs. The researcher concludes that implementing English as Medium Instruction in a bilingual program provides challenges for teachers and students in using English. However, with the challenges by teachers and students face, both also get benefits. Both of them feel that implementing EMI can enhance their English language skills. Both feel better in English than before.