This third part of the study, based on almost 4,600 specimens, deals principally with the genus Alpheus Fabricius, but also included are the species of the genera Athanopsis, Prionalpheus, Batella, and Metalpheus found in Australia. We have also included the Australian species of the closely related family Ogyrididae. Since the publication of Parts I and II, we have received on loan additional collections which have contained two species of the genus Synalpheus which we are describing as new, one species of the genus Athanas and one species of the genus Salmoneus which are new records for Australia; these and other additional records for the species previously reported are contained in Appendix I. Another appendix gives the tabulation of the known distribution of all species known from Australian waters and a zoogeographic summary. This publication also includes the full bibliography for the three parts and a species index.