Landfills that are not equipped with protective liners risk producing leachate that seeps into shallow aquifers, thereby reducing groundwater quality. This issue is particularly relevant in tropical regions, where communities still rely on groundwater as their main source of clean water. This study combines two-dimensional Electrical Resistivity Imaging (ERI) with laboratory-based groundwater quality analysis to map leachate migration pathways and evaluate their impact on shallow aquifers around the Cadika landfill in South Sulawesi, Indonesia. Geophysical data acquisition was conducted on seven profiles using a Wenner–Schlumberger configuration with 30 electrodes spaced 6 m apart, with a profile length of 174 m and an effective investigation depth of ±30 m. The resistivity data was then processed using RES2DINV software with a smoothness-based least-squares inversion algorithm, producing a stable subsurface model with an inversion error (RMS error) of between 1.6% and 10.9%. Interpretation revealed a low resistivity zone (<10 Ωm) in the landfill body extending to the rice fields and residential areas, indicating both horizontal and vertical leachate migration. As verification, groundwater and leachate quality tests were conducted at five sampling points with parameters of pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD₅), and Dissolved Oxygen (DO). The analysis results showed that wells located 25–50 m from the landfill had COD values exceeding the quality standards, while wells located further away showed relatively better water quality. The spatial relationship between the low resistivity zone and the increase in organic pollution indicators confirmed the influence of landfill leachate on the shallow water system. Overall, the integrated approach between the ERI method and groundwater quality analysis is effective in reducing the uncertainty of geophysical interpretation and providing a reliable preliminary evaluation framework for monitoring the impact of landfills on shallow aquifers, particularly in tropical regions with complex hydrogeological conditions.