The effects of climate and land use change on the water balance of the Hadejia River Basin (HRB) were assessed using a combination of climatic, hydrological, and land use prediction models. From 1980 until 2015, Arc-SWAT was utilized for both simulation and prediction. The SWAT-CUP environment was utilized for calibration and validation using the sequential uncertainty fitting approach (SUFI-2). The calibration and validation test results showed that the model was robust, with Nash–Sutcliffe (NS) = 0.72 and 0.63, R2 = 0.74 and 0.66, and PBIAS of 17.8 and 12.2. Two distinct scenarios (the first and the second) were used to run future simulations (2020–2040). Average annual precipitation (23.4%), runoff (2.1%), baseflow (3.7%), streamflow (20.4%), and potential evapotranspiration (PET) (0.82%) all decreased in the first scenario, according to the data. In contrast, the second scenario showed a 12.6% increase in surface runoff but a 27.2% decrease in water yield, indicating LULC consequences that needed to be addressed.