Marine environmental pollution is a longstanding global problem and has a particular impact on the Bay of Bengal. Effluent from different sources directly enters rivers of the region and eventually flows into the Bay of Bengal. This effluent may contain radioactive materials and trace metals and pose a serious threat to the coastal environment, in addition to aquatic ecosystems. Using gamma spectrometry and atomic absorption spectrometry, a comprehensive study was carried out on the radioactivity (²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs) and trace metal (Cd, Pb, Zn, Cu, Ni, Fe, Mn, and Cr) concentrations, respectively, in fish and crustacean species collected from the coastal belt of the Bay of Bengal (Chattogram, Bangladesh). The analysis showed a noticeable increment in the levels of different radioactive pollutants in the marine samples, although the consumption of the studied fish and crustacean species should be considered safe for human health. Anthropogenic radionuclide (¹³⁷Cs) was not detected in any sample. Furthermore, the metal concentrations of a small number of trace elements (Pb, Cd, Cr) were found to be higher in most of the samples, which indicates aquatic fauna are subject to pollution. The estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TR) were calculated and compared with the permissible safety limits. It was found that consuming the seafood from the Bay of Bengal may cause adverse health impacts if consumption and/or means of pollution are not controlled.