Petrolisthes violaceus is a species of porcelain crab endemic to the south-eastern Pacific.

[3] Petrolisthes violaceus' range is from Callao, Peru to the Taitao Peninsula in Chile.

[3] It is a free-living crab, commonly found in crevice, under boulders, or between rocks.

[6] Because of the vertical distribution and its intertidal habitat, P. violaceus is regularly exposed to different periods of air exposure, which varies by the heights of the tides.

P. violaceus is better able to cope with water hypoxia due to its position in the lower intertidal zone; it is proposed that in aquatic conditions, P. violaceus has an oxyconformer strategy and is able to adapt its oxygen demands in an oxygen-fluctuating environment.