This study aims to evaluate Rameshwaram’s groundwater quality in terms of seawater intrusion. The pH ranged from 6.87 to 7.82, and The EC varied between 0.81 and 13.73, 90% below the allowable limit, TDS observed at 240 mg/L to 4103 mg/L with a significance of 70% in the permitted threshold, The range of the Ca hardness was 60 mg/L to 355 mg/L, with 58% exceeding the limit, the range of the Mg hardness was 50 mg/L to 560 mg/L, with 93% surpassing the permitted limit, and the range of the TH ranged from 180 mg/L to 915 mg/L, with 30% exceeding the limit. F- concentrations range from 1 mg/L to 1.78 mg/L, showing 35% are at harmful fluoride levels, while TS concentrations range from 330 mg/L to 4100 mg/L, with over 65% above the limit. According to statistical explanations by rotating component matrix, component 1 achieved 48.53%, component 2 reached 67.64%, and component 3 reached 90.52%. Under Kaiser normalization, the minimum Varimax value fell within the range of 0.81-330.0. The range of possible Varimax values is 8.73 to 25000.60. The standard deviation varied from 0.3264 to 3867.6154, while the mean deviation ranged from 1.8373 to 1661.0150. An identity of 65% found in one group remaining 35% in another cluster. GIS-based spatiotemporal values of water quality metrics confirm the intervention of sea water intrusion in coastal zone. In conclusion, investigation of water quality in the coastal region exhibits the seawater intrusion problem with supporting results of statistical analysis and GIS mapping.