[2] The chelipeds are large and robust and equal in size and lack spines or tubercles, the pereiopods (walking legs) are relatively short and rather stout.

[2] X. hydrophilus closely resembles X. pilipes,[3] from which it can be distinguished by the absence of fringes of setae on the second to fifth pairs of pereiopods (walking legs).

[2] Other key identification features are that the second to fourth pairs of antero-lateral lobes are separated from each other by an inward pointing, wide and shallow depression, the postero-lateral margins of the carapace are bristly and the inner surfaces of the propodus has a broad, longitudinal pitted cavity.

[4] Xantho hydrophilus lives under stones on sandy and stony beaches,[2] below the intertidal zone, up to a depth of 40 metres (130 ft),[3] although it can be found in rock pools at low tide.

[5] Mating takes place in spring, and the females carry the fertilised eggs on their pleopods from March to July; the larvae can be found in the plankton over most of the summer.