Trust is a fundamental element for sustaining student organizations, and its development is strongly influenced by the quality of interpersonal communication among members. Within the Muhammadiyah Student Association (Ikatan Mahasiswa Muhammadiyah/IMM), diverse member backgrounds and organizational dynamics often create challenges in establishing harmonious and trusting relationships. This study aimed to explore the lived experiences of interpersonal communication among IMM members in Samarinda as a means of fostering mutual trust. A qualitative study employing a transcendental phenomenological approach was conducted with ten purposively selected participants, consisting of active members, alumni, and the chairman of the IMM Samarinda branch. Data were collected through in-depth interviews, observations, and documentation, and analyzed using Moustakas' phenomenological analysis supported by NVivo software. Data credibility was ensured through source triangulation, technique triangulation, and member checking. The findings revealed seven major themes: interpersonal communication as the foundation of trust, gradual self-disclosure, interpersonal needs as communication drivers, supportive leadership communication as a catalyst for trust, the role of informal communication in fostering closeness, communication barriers in trust formation, and the greater effectiveness of face-to-face communication compared with digital communication in building trust. The study concludes that trust develops through continuous interaction, self-disclosure, shared experiences, and a supportive communication climate. These findings contribute to the understanding of trust formation by demonstrating that cognitive, affective, and behavioral processes interact to strengthen interpersonal communication within student organizations.