Resumo. Abstract Aim This study aimed to evaluate the spatial and temporal distribution of ichthyoplankton in the Peri Lagoon, a coastal freshwater lagoon in Brazil. Methods Ichthyoplankton samples were collected every two months from June 2008 to April 2010 with 500 µm conical-cylindrical planktonic nets at five sampling stations. Results In total, 181 fish eggs and 1,315 larvae, representing estuarine and freshwater species, were captured. The most representative species were Awaous tajasica, Ctenogobius sp1, and Platanichthys platana. Significant differences were found in temporal egg distribution and larval spatiotemporal distribution (Kruskal-Wallis test, p < 0.05). Eggs were predominantly captured during the autumn, winter, and spring Neotropical seasons. Geospatial analysis demonstrated spatial segregation in the distribution of larval assemblages, with higher abundances in areas adjacent to riparian forests, following stream mouths, and deeper areas with rocky substrates. Conclusions Proximity to streams and areas surrounded by dense forests is crucial for the spawning and development of fish species in the Peri Lagoon. The findings of this study provide valuable insights into the conservation of the ichthyofauna in this unique environment.