An investigation into tectonics and erosion reveals that they play an important role in causing uplifting, valley incision, and soil erosion. The analysis of drainage basins at different scales is irreplaceable in the development of sustainable plans, particularly in arid regions. Morphotectonics and morphometric characterization analyses are very effective methods for defining the evolution of different landforms, current-day tectonic activity, and hydrological and morphological signatures of basins under investigation. The reorganization of critical drainage basins and sub-basin risk priority ranking are essential for effective and accurate sustainable plans for drainage basin management and water resources. In this study, the coupling of geospatial techniques and statistical strategies was used to examine the tectonic activity and priorities in terms of soil erosion for 15 sub-basins of Wadi Al-Lith along the Red Sea coast of Saudi Arabia. Two effective models, namely, the relative tectonic activity model and the weighted sum analysis model, were applied for examining each geomorphological and hydrological characteristic based on an analysis of the morphotectonics and morphometric parameters. Regarding the relative tectonic activity model, the 15 sub-basins were classified into three classes of tectonic activity: low, moderate, and high. Sub-basins 5, 6, 13, and 15 were considered to be in class 1 (high relative tectonic activity). On the other hand, the weighted sum analysis model assigned the sub-basins into three different ranks: low-, moderate-, and high-soil-erosion priorities. The current study’s results suggest that sub-basins 5, 6, 10, 13, and 15 were recorded within the high-soil-erosion zone and highly relative tectonic activity, covering approximately 53.52% of the total sub-basin areas. The relative tectonic activity and weighted sum analysis models proved their validity in the risk studies, which will be very useful for decision makers in various fields, including natural resources and agriculture.