This monograph presents the results of archaeological recording along two South West Water pipelines, between Tintagel and Boscastle and between Harlyn Bay and Padstow. The sequence began with Mesolithic lithics and continued through pits with Early Neolithic ceramics, with Grooved Ware and with Beaker pottery. A Middle Bronze Age roundhouse of unusual character had been submerged by colluvium and produced a mould for a copper alloy racloir, an artefact more commonly found in Continental Europe. There were Bronze Age field walls, and a modified ‘natural’ stone, a focus for prehistoric activity. At Forrabury, uniquely in Cornwall, Early Iron Age cists were revealed, and, close to the well-known later Iron Age cemetery at Harlyn Bay, an Iron Age to Romano-British settlement was uncovered beneath blown sand. The terrain of each pipeline had its own distinctive character and a concluding discussion explores the archaeology of successive periods against this and against the background of Cornish prehistory.