The dissolution of fugitive gases in saline to hypersaline groundwater in arid regions is largely unclear. Groundwater samples from three major oil field aquifers in northern (NK), southeastern (SEK), and western Kuwait (WK) were investigated to determine the concentration, sources, evolution, and distribution of dissolved CH4. Saline NK wells demonstrated the highest concentration of CH4 at 688 mu g/L, followed by WK at 419 mu g/L and SEK at 102 mu g/L. Elevated CH4 concentrations were detected in Na-Cl-SO4 and Na-Cl type groundwater. CH4 hotspots were located in regions with increased lineament intersections and proximity to older wells near the hydrocarbon reservoirs, exhibiting an inverse correlation with conductivity and H2S levels. Microbes in the SEK region utilize carbon substrates, leading to reduced CH4 levels in comparison to NK and WK. delta 13CCH(4) values showed relatively depleted signatures for WK (- 51.2 parts per thousand), while NK displayed enriched values alongside decreasing CH4 levels, indicating thermogenic sources. Enriched delta 13CCH(4) values in SEK (+ 9.5 parts per thousand) are associated with elevated CH4 concentrations. The delta 2HCH(4) values range from - 479 parts per thousand to - 140 parts per thousand, while delta 2HH(2)O values range from + 4 to - 36 parts per thousand, indicating the presence of mixed methanogenic sources across the regions. In NK, the thermogenic methane was observed with variation in isotope signatures due to complex processes. In SEK, although reducing environments prevailed, the carbon isotope fractionation is exceeded by the hydrogen isotope due to the significant impact of microbial oxidation during the diffusive migration process. In the west of Kuwait, the isotopic signatures of methane are depleted, mainly due to the oxidation of organic matter or through Sulfate-Driven Anaerobic Oxidation of Methane (SD-AOM) and carbonate dissolution. Four primary sources of CH4 are microbial, methyl-substrates, carbonate substrates, and mixed sources, which are identified alongside two main processes: biogenic and thermogenic.