The health and productivity of coral reefs is underpinned by the symbiosis between corals and dinoflagellates (Symbiodinium spp.). To enable population genetic analyses of Symbiodinium spp, required for coral reef conservation, seven microsatellite loci were isolated from Symbiodinium clade C from the Great Barrier Reef, Australia. These microsatellite primer pairs consistently amplified between 1 and 8 alleles per coral host colony, with mean number of alleles ranging from 1.9 to 4.0 and generally high genetic diversities (Shannon’s Index = 0.71–2.76). The novel microsatellite loci amplified between 1 and 10 alleles in four other C strains, but did not amplify a D strain. Three of six previously published clade C microsatellite loci amplified 1–6 alleles in two or more of five C strains tested. The primers and cross amplifications presented here therefore provide a useful tool for elucidating the population genetic structure of clade C Symbiodinium populations.