It is native to the northeast Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America, and both Atlantic and Pacific Coasts of North America.

It grows to a carapace width of 90 mm (3.5 in), and feeds on a variety of molluscs, worms, and small crustaceans, potentially impacting a number of fisheries.

Its successful dispersion has occurred via a variety of mechanisms, such as on ships' hulls, packing materials, bivalves moved for aquaculture, and rafting.

In the British Isles, it is generally referred to simply as the shore crab.

The two taxa can be distinguished by the front of the carapace, between the eyes, which is short and toothed in C. maenas, but longer and smoother in C. aestuarii.