Several researchers have suggested that Early Iron Age (i.e., first millennium ad) farmers in the mountainous valleys along the southeastern seaboard of southern Africa moved their livestock in a transhumant or seasonal fashion between grazing areas in order to take advantage of differentiation in availability of pasture. Until now, there have been no data to systematically test this hypothesis. This study presents new zooarchaeological and preliminary strontium isotope data from the Early Iron Age sites of Ndondondwane, Mamba I and Wosi in the lower Thukela River Valley of South Africa. Harvest profiles of domestic stock suggest that herds were present year-round in the valley bottom, despite the advantages of a transhumant pastoral system. In order to resolve the discrepancy between the harvest profiles and the expected mobility patterns, a pilot isotopic study collected modern baseline strontium data in an effort to establish the local valley signature. The isotopic signatures from the zooarchaeological cattle specimens from the three sites show variation between sites, which is indicative of both limited and variable patterns of mobility throughout the valley. In addition, the strontium data suggest that some cattle may have been moved through social and/or economic exchanges from outside the valley.