The increasing presence of international students in Indonesian pesantren (Islamic boarding schools) has created new spaces for intercultural interaction. However, existing research on pesantren has largely focused on religious pedagogy and institutional traditions, with limited attention to intercultural adaptation and identity negotiation within these settings. Drawing on intercultural communication and identity negotiation theory, this study examines how international students at Pesantren Al-Fatah Temboro construct and renegotiate their identities through everyday religious, linguistic, and social practices. The study employs a qualitative case study approach based on in-depth interviews with international students. The analysis explores how students navigate linguistic hierarchies (Indonesian and Javanese), local social norms, food practices, and communal religious activities, including the khuruj (stepping forth) program. The findings show that adaptation extends beyond cultural adjustment to involve continuous negotiation of belonging, authority, and religious identity within the pesantren community. Communal routines and outreach activities function as experiential intercultural learning spaces that foster cultural sensitivity and communicative competence. Conceptually, this study extends intercultural adaptation research by situating identity negotiation within a faith-based residential education context. The findings highlight how religious communal practices serve as institutional mechanisms that shape intercultural competence and offer insights for developing inclusive strategies in transnational Islamic education.