This article reports excavations undertaken between 1990 and 1994 on a small cliff terrace, at Tintagel Island in Cornwall. This terrace (the Lower Terrace) lies below Site C (the Middle Terrace), where a building was excavated by Dr C.A.R. Radford in the 1930s. The remains uncovered on the Lower Terrace comprise several phases of ephemeral stone and turf structures with associated hearths, floor deposits and stakeholes. These are separated by periods of shillet (tiny flakes of slate in sandy clay soil) levelling. With the collapse of the last structure the terrace was buried by layers of scree and slate slip from the slope above. Artefact groups of fire-lighting stones, whetstones and worked flint and quartz were recovered predominantly from earlier phases, together with Romano-British Native pottery. Later phases mainly comprised sherds of Imported Mediterranean pottery (84 per cent of all finds) and slate disc pot lids. The results of an extensive programme of environmental sampling clarified that a wide range of probably locally growing trees and shrubs were exploited for fuel, as well as for wattles and larger posts and beams. Tiny burnt fragments of animal and some human bone were found scattered through a handful of deposits, but the material is probably residual. A programme of radiocarbon dating was possible with the availability of charcoal material from hearths and stakeholes. This programme, using innovative mathematical modelling techniques, produced three distinct date ranges of structural activity on the Lower Terrace: 395–460 cal AD for one of the earliest phases of hearths, floors and stakeholes pre-dating the occurrence of Imported pottery; 415–535 cal AD for a later structural phase with hearths and first occurrences of Imported and Native pottery together; and 560–670 cal AD for the latest and best surviving structure, with hearths, stakeholes and a large assemblage of Imported pottery.