The warming rates in many mountain areas are higher than the global average, negatively impacting crop systems. Little is known about the climatic changes which are already being observed in eastern Democratic Republic (DR) of Congo, due to the lack of long-term meteorological data. Local perceptions could help us to understand not only the climatic changes and impacts but also which adaptation strategies are already being used by local smallholder farmers. Semi-structured questionnaires were administered to 300 smallholder Bafuliru (n = 150) and Lega (n = 150) farmers living in the Itombwe Mountains. The respondents reported climatic changes and impacts, with the Bafuliru—living on the eastern drier slopes—reporting more changes and impacts. While the Bafuliru were implementing several adaptation strategies (e.g., increased irrigation and use of inputs, more soil conservation, more income diversification), the Lega were implementing very few, due to soft limits (access to inputs, markets, and information) and culture (less interest in farming, less capacity to organize into groups). The results highlight important differences in sociocultural contexts, even for one ‘remote’ mountain, calling for a more collaborative approach to adaptation planning and action.