The study was conducted as part of the Joint Vietnam–Russia Tropical Science and Technology Research Center’s project on indicator organisms in the marine environment of south-central Vietnam. The research focused on coastal areas with significant anthropogenic impacts, revealing that biological resources directly affect the livelihood and activities of coastal populations. These resources are dynamic and subject to both human and natural factors. The material from the soft-bottom zone was collected using a grab rake with a mesh bag at the end. Scuba diving equipment was used in areas with a hard substrate and mudflats. In addition, during sample collection, several mollusc specimens were acquired from fishermen who cought marine organisms in that lagoon. Comparing the results with previous studies on bivalve resources in the area, the Nha Phu Lagoon was found to harbour a wide range of economically valuable bivalve species. A total of twenty-seven bivalve species from thirteen families were identified, with the family Veneridae having the highest number of species (eight). The most abundant catches were from the families Ostreidae and Mytilidae, primarily consisting of Magallana gigas (Thunberg 1793) and Perna viridis (Linnaeus 1758), both cultured in the lagoon. Apart from their economic value, these two species also play crucial roles in the ecosystem by filtering water and retaining organic debris in the environment.