Estuaries, the interface between riverine systems and coastal environments, have great archaeological potential for interdisciplinary research. Extensive survey of 25km of coast in the Severn Estuary, Wales, databased using Autocad and GIS, is combined with more detailed investigation of 3km at Goldcliff. This demonstrates that coastal wetlands can preserve a diverse range of site types which contrasts with both terrestrial dryland contexts and other wetlands, such as the nearby Somerset Levels. Rectangular Bronze and Iron Age buildings, unique in Britain, trackways and other post settings are exposed on intertidal peat shelves. Activity on these former wetlands was particularly concentrated at the interface with marine flooding in the later Bronze Age and Iron Age, periods of major... environmental change in both estuarine and riverine environments of the Severn. Activity seems to have been essentially opportunistic and seasonal, with evidence for cattle grazing and perhaps fishing. Marine inundation in the Iron Age was followed by Romano-British reclamation.