<p>Weizhou Island is the largest and youngest volcanic island in China, and has a great variety of marine organisms. However, the composition and distribution of its oysters are less known. To determine the diversity and distribution of oysters from Weizhou Island, 308 individuals were collected from 10 intertidal and 10 subtidal sites. All the samples were identified based on their morphological characteristics and mitochondrial 16S rRNA gene sequences. Our results indicate 13 Ostreoidea species from five genera existed on Weizhou Island. Among them, eight species were distributed in the intertidal zone (<i>Crassostrea sikamea, C. gigas angulata, Saccostrea echinata, S. malabonensis, S. circumsuta, S. mordax, S. spathulata</i>, and <i>Dendostrea folium</i>) and six species were distributed in subtidal zone (<i>Hyotissa hyotis, H. sinensis, H. inaequivalvis, Hyotissa</i> sp., <i>Booneostrea subucula</i>, and <i>Dendostrea folium</i>). Of these, <i>S. spathulata</i> was a new record species in China. An unassigned species belonged to the genus <i>Hyotissa</i> Stenzel, 1971 and was closely related to <i>H. inaequivalvis.</i> Weizhou Island exhibites high species-level oyster diversity. The dominant species in the intertidal zone was <i>S. echinata</i>, which accounted for 51% of the total species in intertidal samples. The dominant species in subtidal zone was <i>H. inaequivalvis</i>, accounted for 58% of the species found in subtidal zone. Our results provide a scientific basis for the reasonable development and management of oyster resources in the Weizhou Island, China.</p>