ABSTRACT Natar Fampompar is a stone boat ceremonial structure (natar) in the village of Sangliat Dol on Yamdena Island, Tanimbar Islands, Island Southeast Asia. Located in the village center, it is the only Tanimbarese natar that continues to be used for clan meetings and ceremonial events. As such, it arguably represents the most significant cultural site for understanding Tanimbarese tradition. This article documents the Natar Fampompar and six associated cultural heritage sites. We discuss their historical origins and relevance to the people of Sangliat Dol; how maritime cosmology and maritime identity are evident in social organization, settlement organization, ceremonies, and people’s daily lives; and the function of natar before and after the introduction of Christianity. Initial archaeological work is reported. Finally, this research raises the issue of heritage theft and sale, particularly the carved prow stones of the Natar Fampompar, and how the people of Sangliat Dol hope for their return.