A series of biological surveys of crustaceans in Siaolanyu were carried out. Those conducted during May 22-26, July 7-11, August 19-26, October 17-19 and November 25-26, 2009 were focused on intertidal zones and freshwater ponds, whereas those conducted during May 18-20 and September 10-11 were focused on sub-tidal zones. Images of living creatures under the sea were captured on film by scuba divers and were brought back to the laboratory for further examination. A total of 68 species in 48 genera, 25 families, 6 orders, and 3 classes were identified. Among them, four species, two in Class Branchiopoda and two in Class Malacostraca, were discovered in Taiwan for the very first time.