The authors regret that the printed version of the above article is missing an abstract. The Abstract follows. The authors would like to apologise for any inconvenience caused. Abstract: Sandy beach surf clams of the genus Mesodesma represent a valuable resource along the Atlantic and Pacific coasts of South America. Along the coast of Chile and Perú, Mesodesma donacium is one of the most important shellfish species exploited. This species recruits and inhabits sandy beaches, where burial behaviour is a vital adaptation to avoid predation. In Chile, desalination plants are playing an increasingly important role in response to drought-induced challenges. Consequently, the implementation of seawater desalination plants in Central-Northern Chile has been promoted, but the consequences for local coastal organisms are largely unknown. In this study, small M. donacium juveniles were used to assess the effects of reverse osmosis desalination plant discharges on coastal organisms. In the laboratory, the clams were exposed to different brine concentrations to assess their impact on survival and sub-lethal traits, such as burial success, time, and metabolism. The results showed no impact on clam survival from brine discharges. However, undiluted saline brines (56–58 PSU) and salinities above 38 PSU resulted in sub-lethal effects, including reduced burial success, increased burial time, and higher metabolic rates. These negative sub-lethal brine impacts will primarily occur in the vicinity of the discharge point, directly around the outfalls, where the salinity anomalies surpass the ambient variability. To mitigate potential adverse effects on M. donacium, we recommend implementing measures to minimize the area of impact. This can be achieved by positioning the discharge point in strongly hydrodynamic areas or as far away as possible from areas inhabited by small surf clams or similar organisms. Additionally, we recommend using diffusers to increase mixing and brine dilution to sub-lethal levels (below 38 PSU)