Natural and anthropogenic-induced changes in sea surface temperature (SST) affect all marine organisms, including the critical larval stages of coastal invertebrate species. Changes in sea surface temperature affect larval stages that must respond to these changes behaviourally, physiologically and, in some cases, alter morphological traits. Here, we evaluated the effects of rearing temperature on starvation-survival, swimming performance and morphology of zoea 1 larvae of the kelp crab (Taliepus dentatus). Females were acclimatised to 15 degrees C, the average SST in the study region, until larval hatching. Rapid exposure of unfed larvae to 12 degrees C significantly reduced starvation-survival (LT50), whereas no significant differences were found between 15 degrees C and 17 degrees C. Larvae swam faster but for less time at 12 compared to 15 degrees C and 17 degrees C. Exposure to temperature induced changes in the dorsal spine shape, which were apparent after only 24 h of exposure to altered temperature and increased after 8 days. Overall, our results suggest that exposure to temperature can rapidly alter the shape, survival and swimming performance of larvae, inducing different energy-demanding behavioural responses. We contend that water temperature on marine invertebrate larvae can significantly impact their physiology and morphology even after a few hours of exposure, and we suggest that future studies should define environmentally relevant variation when setting lab-based experiments in order to correctly extrapolate laboratory results within the variable coastal environments.