Santa Catalina Island is a small island off the coast of southern California and for its modest size harbors several species of flies from the Drosophila genus. We performed an island-wide survey of Drosophila species to ascertain which species were endemic to the island and where they were most abundant. In doing so, we have assembled useful sampling information for researchers who wish to conduct field studies on Santa Catalina Island. We recorded the abundances of flies from the repleta subspecies group as well as non-repleta species. Additionally, we performed seasonal collections over one year at two locations on the island (Little Harbor Campgrounds and Wrigley Marine Science Center) to assess the best season for collections. From this seasonal survey, we observed that species abundance and composition at these two sites greatly vary in the time that we sampled. One of the seasonal sites that was sampled in two consecutive summer seasons showed that species composition had shifted between years, but relative species abundances were approximately the same.