It has rough bark to the thinnest branches, lance-shaped or curved adult leaves, club-shaped flower buds arranged in groups of between seven and fifteen, white flowers and hemispherical to more or less spherical fruit.Eucalyptus arenacea is a tree with several to many stems or a robust mallee, grows to a height of 3–10 metres (10–30 ft) and forms a lignotuber.

It has rough, fibrous and stringy bark on its trunk and to the thinnest branches.

The flowers are borne in groups of between seven and fifteen in leaf axils on a peduncle 5–18 mm (0.20–0.71 in) long, the individual buds on a pedicel 2–5 mm (0.079–0.20 in) long.

[3][4][5] Eucalyptus arenacea was first formally described in 1988 by Julie Marginson and Pauline Ladiges and the description was published in Australian Systematic Botany.

[6] The specific epithet (arenacea) is a Latin word meaning "of sand".