In response to drought challenges in Chile, desalination plants are becoming crucial. Consequently, the implementation of more osmosis reverse desalination plants in central-northern Chile has been promoted, but the consequences of brine discharges on local organisms are largely unknown. The Chilean abalone (Concholepas concholepas) represent the most economically important marine resource exploited along the Chilean coast. In this study, newly hatched larvae of C. concholepas were used to investigate the effects of brine discharges of a reverse osmosis desalination plant on coastal organisms. Under laboratory conditions, larvae were exposed to various dilutions of a brine to assess the consequences on lethal (survival) and sublethal (swimming performance and metabolism) traits. The results indicated that brine discharges had no effects on larval survival. However, undiluted brines (ca. 56 PSU) and salinities above 38 PSU led to increased metabolic rates and a reduction in the swimming performance of the larvae. We suggest mitigating the negative effects of brines on newly hatched C. concholepas larvae by situating discharge points in highly hydrodynamic zones or as far as possible from mating and larval hatching areas. Additionally, we recommended using diffusers to enhance mixing and dilute brine to sub -lethal levels (below 48 PSU).