The border is a strategic area within the Republic of Indonesia because it has potential natural resources and market opportunities and is related to aspects of sovereignty, defense and security. The division of the Papua region based on astronomical lines causes the traditional region, inhabited by tribes with the same spiritual-culture, to be divided into two countries. The Kanum tribe, who live in the border region of PNG and Indonesia, have close kinship relations. This research aims to analyze the social interactions of cross-border communities, especially the interdependence of the Kanum Tribe in Sota, Merauke Regency, with Papua New Guinea. The research used social interaction theory and interdependence theory, as well as qualitative descriptive methods by interviewing 15 informants. The research results support Polanyi’s statement but refute Omolomo’s, confirm positive competition, and eliminate indicators of conflict in the social interactions of the Kanum Tribe. The main problem found was unclear population data for the Kanum community who live in PNG but receive facilities from Indonesia. The dominant inhibiting factor comes from the PNG border condition, and the dominant supporting factor comes from the Sota border conditions (geography, infrastructure, economics and government policy). However, the condition that is equally a during factor in the conditions of the PNG and Sota borders is culture.