The contribution made by saltmarsh to the production of estuarine zooplankton was examined through a comparison of inputs and outputs of tidal water at a site on Towra Point, NSW, Australia. Saltmarsh proved to be a net exporter of crab and gastropod larvae, although it functioned as a sink for copepods and amphipods. Further, the highest density of zooplankton in estuarine nearshore habitats (saltmarsh, mangrove, seagrass, and open water) during a high tide event was found in the saltmarsh. The presence of high concentrations of zooplankton, predominantly crab and gastropod larvae, in the saltmarsh and lesser extent in the mangrove represents a source of food for estuarine fish.