Assessing the climate change impacts on hydrologic phases is crucial in order to establish adaptive management strategies for water resources. These assessments are performed by utilizing projected climate change trends for hydrologic model input data to forecast future hydrological processes. The soil and water assessment tool (SWAT) is a well-used hydrologic modelling tool that has been implemented in diverse hydrologic and environmental conditions investigating climate change impacts. This study assesses the potential future climate change effects on the hydrologic phases in the Aggitis River Basin. The SWAT daily streamflow results after being calibrated and validated were very good. Two climate change scenarios (RCP4.5 and RCP8.5) of the WCRP-CMIP3 multi-model dataset were applied. The future (2025–2100) modelled hydrologic conditions showed that, compared to the baseline conditions (1979 to 2022), there will be an average increase in evapotranspiration's participation in the hydrologic cycle from 47% to 74% and 77% for the RCP4.5 and RCP8.5 scenarios, respectively. At the same time, there will be a decrease in groundwater recharge by 61% and 69% under these future scenarios and an overall water yield loss of half (from 16% to 7-8%). Climate change is expected to alter the hydrological regime and will impact the water supply and demand for agriculture. Thus, monitoring and preparation are necessary in planning the water demand at the basin scale. There is a vast range of nature-based solutions and ecosystem-based approaches that aim to increase resilience to climate change and sustain the rural activities and communities.