Marine sponges are the single best source of potential anti-cancer drugs from the marine environment. This study was to search for novel chemotherapeutic compounds from marine sponges collected from the South Australia coastline. Non-polar extracts from twelve sponge species were screened for anti-cancer activity against five human cancer cell lines: colon cancer DLD-1, lung cancer A-549, breast cancer MCF-7, cervical cancer Hela, and prostate cancer DU-145. Ten out of twelve species tested showed anti-proliferative effect on all five cell lines tested, especially A-549, as detected by the Crystal Violet assay. The IC₅₀ values ranged from 1.0 to 40 µg/ml. The anti-cancer activity induced by the sponge extracts was found to be associated with apoptosis induction and cell cycle arrest in G₁ phase. To identify the active compounds, the most active extract from the sponge Acarnid sp. was selected for fractionation using n-hexane (F1), dichloromethane (F2), butanol (F3), 50% methanol (F4), and 100% methanol (F5). The cytotoxicity of each fraction was tested on the A-549 cell line. F2 and F3 were found to be active, with IC₅₀ values of 0.5 and 5 µg/ml, respectively. Anti-invasive activity of F2 and F3 on A-549 cell line was investigated at non-toxic concentrations. F2 treatment (0.25 µg/ml) inhibited the abilities of motility (approximately 40%), migration (57%), and invasion (72%) of A-549 cells compared with the untreated control, as detected by the Wound Healing, Migration and Matrigel Invasion Boyden chamber assays. However, F3 did not show anti-invasive activity under the tested conditions. Taken together, the sponge extracts from South Australia Waters exhibit a broad spectrum of anti-cancer activities. These extracts are currently undergoing further analysis to identify the active constituents and to investigate the underlying anti-cancer mechanisms.