This article investigates the construction of the religious identity of the indigenous Orang Lom of Mapur Bangka, Indonesia, and its transformation during contact with state formal religions of Indonesia. This research is ethnographically based on the observation and separate interviews involving key figures of the tribe, such as the Customary Chairperson, and the numerous members of the tribe. The result of the study indicated that Orang Lom still maintains their beliefs and the tribal cultural practice are still dominant. The contiguity between Orang Lom belief and formal religions particularly Islam has implications for non-sacred cultural practices, while sacred practices are still well preserved.