Luidia australiae, the southern sand star, is a species of starfish in the family Luidiidae.

It is found in the Pacific Ocean around Australia and New Zealand.

The central disc and the arms are a dull yellow colour, irregularly blotched with dark green or black.

It is found on reefs, in seagrass meadows, and semi-buried in sand at depths of up to 110 metres (360 ft).

Luidia australiae is a carnivore and is often found half-buried in the sediment in seagrass beds where its colouring provides camouflage.