The Sound of Mull Archaeological Project (SOMAP) was carried out between 1994 and 2005 to map and assess the condition of a wide range of underwater and interdidal wrecks and coastal structures in the Sound of Mull, on Scotland's north-west coast. The study was undertaken by many volunteers under the auspices of the Nautical Archaeology Society and demonstrates the value of projects carried out by trained volunteers. This account of the project combines the results of documentary research into archives and old photographs, high resolution marine geophysics, and measured surveys both on land and underwater. A total of 16 wrecks and four sites were examined and are summarised, with detailed accounts of three sites of wrecks or shipping-related debris of particular interest. An accompanying CD includes a wide range of remote-sensing images.