Climate change is one of the main threats to the sustainable management of water in various regions of the world, especially in mountainous watersheds like the Mantaro River basin, located in the highland region of Peru. This basin is vital for agriculture and hydroelectric energy production in the area, but it faces significant challenges due to the variability of water resources and climate change. To mitigate these effects, there is a recognized need to identify suitable areas for the storage and distribution of rainwater. In this study, thematic maps of the basin were created using the technique of multi-criteria analysis, considering factors such as precipitation, soil type, slope, texture, and watershed order. Four climate change scenarios (RCP 2.5, RCP 4.5, RCP 6.0, and RCP 8.5) were also included to assess their impact on potential areas for rainwater harvesting. It was identified that approximately XX% of the lower lands in the basin, with a flat topography, are suitable for the implementation of rainwater harvesting systems. However, the low amount of precipitation in these areas, compared to the highlands, represents a significant challenge. Regarding the climate change scenarios, it was determined that under the RCP 2.5 and RCP 8.5 scenarios, the upper areas of the basin, which comprise approximately XX% of it, would be the most suitable for the implementation of these infrastructures. On the other hand, with the RCP 4.5 and RCP 6.0 scenarios, the mid-altitude areas, which cover about XX% of the basin, would be the most strategic.