One of the most difficult types of land-related conflict is that between Indigenous peoples and third parties, such as settler farmers or companies looking for new opportunities who are encroaching on Indigenous communal lands. Nearly 30% of Colombia’s territory is legally owned by Indigenous peoples. This article focuses on boundary conflicts between Indigenous peoples and neighbouring settler farmers in the Cumaribo municipality in Colombia. Boundary conflicts here raise fierce tensions: discrimination of the others and perceived unlawful occupation of land. At the request of Colombia’s rural cadastre (Instituto Geográfico Agustín Codazzi (IGAC)), the Dutch cadastre (Kadaster) applied the fit-for-purpose (FFP) land administration approach in three Indigenous Sikuani reserves in Cumaribo to analyse how participatory mapping can provide a trustworthy basis for conflict resolution. The participatory FFP approach was used to map land conflicts between the reserves and the neighbouring settler farmers and to discuss possible solutions of overlapping claims with all parties involved. Both Indigenous leaders and neighbouring settler farmers measured their perceived claims in the field, after a thorough socialisation process and a social cartography session. In a public inspection, field measurements were shown, with the presence of the cadastral authority IGAC. Showing and discussing the results with all stakeholders helped to clarify the conflicts, to reduce the conflict to specific, relatively small, geographical areas, and to define concrete steps towards solutions.