Camouflage is one of the most widespread means of avoiding predation and to better match their surroundings many animals change colour. However, environmental stress, such as that caused by climate change, may impact colour change and development and thus the effectiveness of predator avoidance. Predator-prey relationships are major forces structuring marine ecosystems, so understanding how they will be affected by climate change is critical to predicting how these ecosystems will respond. Furthermore, on a fundamental level, little work has directly tested how colour change and developmental plasticity is affected by ambient temperature. We investigated how climate-related stressors, in particular seawater temperature, influence colour change and camouflage development in the shore crab (Carcinus maenas). By placing individuals on different backgrounds and photographing them at regular intervals their colour change can be monitored over time across a range of temperatures. Here, we show that juvenile shore crabs are capable of substantial colour change with successive moults, better matching their background with respect to predator vision from one moult to the next. In addition, colour change and moulting, and therefore camouflage, occurs faster with increasing seawater temperature. This indicates that shore crabs may better evade detection as oceans warm. These findings have implications for how predator-prey dynamics will respond to climate change in the intertidal zone, and how camouflage is mediated by developmental processes.