<p>Groundwater quality in coastal aquifers is increasingly threatened by saline water intrusion, yet understanding the geochemical signatures and factors driving groundwater salinization remains a dynamic area of research. In this regard, the present study investigates the hydrogeochemical characteristics and identifies the key sources influencing groundwater chemistry and salinisation in a coastal region of Jagatsinghpur district in Odisha. A quantitative assessment was conducted on thirty-three groundwater samples over two seasons, analysing thirteen physicochemical parameters. The findings suggested that the groundwater is slightly alkaline, with a cationic composition predominantly consisting of Na⁺, Ca²⁺, and Mg²⁺ while the anion composition is dominated by Cl⁻, HCO₃⁻, and SO₄²⁻. Water quality index (WQI) analysis classified 46% of samples as unsuitable for human consumption. Ionic ratios and base exchange studies reveal seawater influence in nearly 50% of drinking water wells. Hydrogeochemical facies studies indicate that the groundwater predominantly falls under Na-Cl and Ca–Mg–Cl type. The HFE diagram indicates the prominence of the cation exchange mechanism of Ca²⁺ with Na⁺ for the salinity on groundwater. The adverse impact of saline recharge and dilution are more pronounced during the post-monsoon season as compared to the pre-monsoon season. The Principal Component Analysis (PCA) supports the influence of saltwater intrusion and anthropogenic activities on groundwater contamination. The land use pattern also underscores the impact of overexploitation and other anthropogenic activities on groundwater quality. This emphasizes the necessity for continuous monitoring and systematic assessment of groundwater quality to mitigate the impacts of saltwater intrusion and ensure sustainable groundwater management in the region.</p>