Ligia dilatata is a woodlouse in the family Ligiidae.

The antennae of L. dilatata are longer, reaching the end of its thorax.

[3] Ligia dilatata feeds extensively on dislodged Ecklonia maxima and Laminaria pallida that wash up on shore.

Females start reproducing at 12 months but, unlike males, probably do not survive to breed twice.

Growth is slow during summer but faster in winter when food is more plentiful.