Temporal patterns of larval occurrence of brachyuran taxa were described from Saco mangrove creek, Mozambique, based on plankton samples. Brachyuran larvae were collected hourly in four 24 h cycles during neap and spring tidal periods at a fixed station, in November 1997 and February 1998. Results indicate a semilunar cycle of larval release activity for most species. Newly-hatched stages of sesarmids showed a peak occurrence in post-crepuscular ebbing tides, Macrophthalmus spp. and Uca spp. showed highest densities during ebbing tides at night. Dotilla fenestrata and Pinnotheridae, in spite of showing a semilunar pattern, did not display significant differences between day and night. Most mangrove taxa showed thus a clear larval exportation behaviour during ebb tides, with little return during the following floods, with varying degrees of dependence on the diel period. Megalopae were restricted to the night period, and highest values were obtained during spring tidal periods. However, maximum values of megalopae were obtained both during flood and ebb periods, contrary to most previous studies. This is interpreted as a bi-directional transport of non-competent megalopae into and from the mangrove area.