Radioactivity is a form of natural radiation, and it is measured in becquerels (Bq) using the SI system. Both human activities and natural processes can produce radioactivity. For this study, three regions on the South Tamilnadu coastline in India, namely Manavalakurichi, Colachel, and Kudankulam, were chosen. A dual-channel alpha-beta counter was used to measure gross alpha and beta activity based on the scintillation principle. The radioactive nuclide activity concentrations in soil and water were measured, and the levels were considered acceptable. The alpha and beta radiation levels in soil and water samples did not significantly differ. The study's results suggest that the risk of radiation danger in the study area is not significantly increased because the values obtained are within the generally accepted limits. The ANOVA experiments also revealed that there was no significant difference in the gross alpha and beta activity of soil and water samples. Moreover, the alpha and beta activity in drinking water was lower in all three areas than what is recommended by the WHO. Therefore, it can be concluded that the drinking water in these three regions is safe for consumption.