Previous archaeological research in Trang Province, on the western coast of southern Thailand, revealed the presence of prehistoric (c. 10,000-3500 BP) and early historic sites (c. 1300 BP). No data are available in the region for the period between 3500 and 1300 BP. The paper presents the results of excavations at Khao Khuram site in Khao Kop village, Huai Yot District, Trang Province. the site was excavated stratigraphically with the systematic collection of data and comprehensive sampling for scientific dating (AMS and OSL). Two samples of rice grains and one sample of soil yielded dates of 1620±30BP, 1560±30 BP, and 1670±113 BP, respectively, indicating that Khao Khuram was inhabited in the late 4th and early 5th centuries CE. Chemical analyses (PXRF and SEM) was also performed on beads, iron tools, a small piece of gold object and bronze bowl. The inhabitant were hunter-gatherers, fisherman, farmers, weavers, metalsmiths, as witness by stone tools, a large amount of animal bones, bone tools, fish bones and fish hooks, clay bullets, rice gains, spindle whorls, potsherds, clay molds, high tin bronze bowls, iron slag, clay tuyeres, and iron tools. Carnelian ornaments, glass beads, two glass balls and a small piece of gold sheet are identified as imported items, suggesting communication and trade with the external communities. This inland site is on the trans-peninsular route. It is concluded that Khao Khuram is a potential site of transitional period; i.e., between the late prehistory and early history.