It is a slender climber or twiner with narrowly elliptic leaves and bell-shaped, greenish-yellow flowers that turn bluish as they age.

The flowers are usually arranged singly in upper leaf axils or on the ends of branches, on a slender, pendent peduncle 12–45 mm (0.47–1.77 in) long.

The petals are 12–23 mm (0.47–0.91 in) long, greenish-yellow, tinged with navy blue as they age, and joined at the base to form a bell-shaped tube, the lobes spreading but not curved backwards.

Flowering mainly occurs from September to January and the mature fruit is a glabrous green berry 10–20 mm (0.39–0.79 in) long, containing many seeds.

[4] Billardiera mutabilis was first formally described in 1806 by Richard Anthony Salisbury in Paradisus Londinensis from a specimen collected by William Paterson.