Intertidal environments experience low salinity during heavy rainfall, creating stressful conditions for organisms, including invertebrate pelagic larvae, which can affect post-metamorphic development. Salinity in tide pools was monitored at low tide during a rainfall event in November 2013 at Puerto Montt, southern Chile. Water samples were taken to identify the presence and size of veligers of the gastropod Crepipatella peruviana. In addition, newly hatched veligers were exposed to different salinities [32 (control), 25, 20, and 15] in the laboratory for 6 h and then cultured at the control salinity until metamorphosis. Shell length (SL), oxygen consumption (OCR) and clearance (CR) rates of juveniles, and survival and growth in the first 2 weeks post-metamorphosis were quantified. The salinity of tide pools decreased to ten during heavy rains and yet contained an abundance of living veliger larvae; more than 85 % of the C. peruviana veligers collected had a SL ≤400 µm, which implies that they had only recently hatched. Exposing early veligers to low salinities (15 and 20) decreased size at metamorphosis and early juvenile survival by approximately 10 and 20 %, respectively. Also, the CR was lower at 5 days post-metamorphosis, decreasing by 30 % in individuals that had been exposed to salinity 15 as larvae. However, the OCR (5 and 15 days post-metamorphosis) and CR (15 days post-metamorphosis) were not different from the control treatment with an average value of 1.7 (×10⁻² mg O₂ h⁻¹ juv⁻¹) and 0.07 (L h⁻¹ juv⁻¹) for OCR and CR at 15 days post-metamorphosis, respectively. Also there was no effect on juvenile growth rate. This study shows that short hyposaline events suffered by early veligers of C. peruviana can cause reduced size at metamorphosis and potentially reduce juvenile survival, factors that could affect the fitness of future adult populations.