Education in the current era of globalization requires schools to be able to create students to have the skills to face the challenges of the 21st century. This effort is in accordance with the objectives of science, technology, engineering, and mathematics (STEM)-based learning which is directed to stimulate students in applying concepts from various disciplines. This study was conducted to analyze students' communication skills in STEM learning using an engineering design process approach. The study involved seven junior high school students as participants, who were selected using a purposive sampling technique. The students accomplished STEM design-based learning through a "Rube Goldberg Machine" project. Data were collected by observation, interview, and documentation methods. Analysis of the research results using a thematic analysis approach is directed to understand students' communication skills in STEM learning. The results showed that students' communication skills were clearly exhibited at each stage of the engineering design process in STEM learning. This research is expected to be a reference in developing students' communication skills in EDP-based STEM learning.