The findings of a week-long survey of coastal marine molluscs around King Island are documented. In total, 408 species were recorded, 78 for the first time. King Island appears to be the only Tasmanian outpost for 44 species. Only two non-native species were found. A number of usually distinct species-pairs or groups appear to form intergrades around King Island. Along the island’s east coast, beached shells belonging to Quaternary-era sub-fossils were found, not all of which are represented in the contemporary local fauna. Following critical examination of published sources and museum specimens, a checklist of King Island’s coastal marine mollusc fauna is presented, comprising 619 species. It is likely that many more local species await discovery and documentation.