Rissoides desmaresti is a species of mantis shrimp native to the eastern Atlantic Ocean and Mediterranean Sea.

[2] Around Great Britain, there have been a few observations from the English Channel and North Wales,[3][4] but the only place where significant numbers are known to occur is on a 25-hectare (62-acre) site east of Saint Tudwal's Islands in Tremadog Bay.

[5] Its occurrence there may be related to warm currents coming from the Bay of Biscay and the sheltered nature of the area.

[5] R. desmaresti has a dorso-ventrally flattened body and may reach a size of 70 millimetres (2.8 in).

[4] It lives in burrows below from the subtidal zone down to depths of around 40 metres (130 ft).