Coastal and estuarine systems provide critical shark habitats due to their relatively high productivity and shallow, protected waters. The young (neonates, young-of-the-year and juveniles) of many coastal shark species occupy a diverse range of habitats and areas where they experience environmental variability, including acute and seasonal shifts in local salinities and temperatures. Although the location and functioning of essential shark habitats has been a focus in recent shark research, data paucity from the South Pacific is evident. In this study, we document the temporal and spatial distribution, age class composition and environmental parameters of young bull sharks (Carcharhinus leucas) in the Rewa, Sigatoka and Navua Rivers, Fiji’s three largest riverine systems. One-hundred and seventy-two young bull sharks were captured from January 2016 to April 2018. The vast majority of the captures were neonates. Seasonality in patterns of occurrence of neonate individuals suggests a defined parturition period during summer. Environmental parameters between the Rewa and the Sigatoka River differed significantly, as did the recorded young bull sharks abundance. According to the surveys, young bull sharks occur in all three rivers with the Rewa River likely representing essential habitats for newly born bull sharks.