<p>Groundwater is a vital global resource, providing approximately 98% of the Earth’s accessible freshwater. However, its quality is increasingly threatened by contamination from both natural and anthropogenic sources. This study investigates the hydrochemical characteristics and uranium isotope composition of groundwater in the Tabuk region of Saudi Arabia. A total of 15 groundwater samples were collected and analyzed for physicochemical properties, major ion composition, and uranium isotopic ratios using alpha spectrometry. Results indicate that groundwater samples exhibited a wide range of total dissolved solids (TDS) concentrations (411–11,167&#xa0;mg L⁻¹), electrical conductivity (626–21,733 µS cm⁻¹), and major ion concentrations, with several exceeding the World Health Organization (WHO) permissible limits. Uranium activity concentrations varied between 0.380 and 0.877&#xa0;Bq L⁻¹, with ²³⁴U/²³⁸U activity ratios ranging from 1.24 to 1.50, suggesting preferential leaching of ²³⁴U due to alpha recoil effects. Principal component analysis (PCA) revealed that uranium concentrations correlated with bicarbonate (HCO₃⁻) and pH, indicating that carbonate complexation plays a key role in uranium mobilization. The findings highlight the importance of hydrogeochemical processes in determining groundwater quality and suggest that ongoing monitoring is essential for sustainable groundwater management in the region.</p>