This document sets out the results from an archaeological watching brief carried out by the Sussex Archaeological Society and West Sussex Archaeology Ltd. on behalf of Portsmouth Water at Fishbourne Roman Palace, Fishbourne, West Sussex. The watching brief was carried out in September 2010 during repairs to the water main. The results included the re-discovery of a tile culvert, first noted by Cunliffe in the 1960's excavations, and the discovery of a previously unknown ditch, which pre-dates the culvert, adjacent to the north-west corner of the north wing.