The St Peter Suite in the southwestern Gawler Craton has been identified as an unusual set of magmatic rocks, with a distinct geochemistry to other Proterozoic magmatic suites of the region. Isotopically, the St Peter Suite is relatively juvenile and represents an addition of mantle material into the crust of the Gawler Craton. This article presents preliminary observations from recent field investigations of the coastal exposures of the St Peter Suite, between Slade Point (south of Streaky Bay) to west of Point James (west of Ceduna). The observations outline three main lithological associations within the exposed St Peter Suite. The presence of both felsic and mafic magma chambers, along with zones of magma transfer shows the complexity present within the suite. Subsequent investigations are underway into the petrological and isotopic evolution of the St Peter Suite that will provide further information towards improving our understanding of this rock suite, its mineral potential, and its place in the geological evolution of South Australia.