Five species of seahorse have been recorded in South Australian waters. Their conservation statuses are generally regarded as data deficient, yet all are fully protected from fishing or collection in South Australian waters, under the Fisheries Management Act 2007.
Observation records on iNaturalist suggest that the Short snouted seahorse (Hippocampus breviceps) is the most commonly encountered by divers or snorkellers.
| Genus | Species | Common name | Described |
| Hippocampus | breviceps | Short snouted seahorse | 1869, Peters |
| Hippocampus | abdominalis | Bigbelly seahorse | 1827, Lesson |
| Hippocampus | whitei | Common seahorse | 1855, Bleeker |
| Hippocampus | bleekeri | Australian pot-belly seahorse | 1908, Fowler |
| Hippocampus | tristis | Dull seahorse | 1872, Castelnau |