The Caution Bay archaeological project on the south coast of mainland Papua New Guinea has excavated 122 sites over a 9 km² area. Lapita ceramics appear at a number of sites at c. 2900 cal. BP. Here we present the results of excavations at Moiapu 3, a site that helps define the end of the dentate-stamped Lapita phase of this region. It is suggested that the decline and ultimate cessation of dentate stamping related to a loss of symbolism during a period of major socioeconomic readjustment and innovation.