It is native to the northeastern Atlantic Ocean and the Mediterranean Sea, where it forms encrusting colonies on rocks and other hard surfaces.

Oscarella lobularis is an encrusting sponge that forms a thick layer of soft, gelatinous consistency with a velvety surface, on rocks, stones and large seaweeds.

It is usually some shade of yellow or brown but can occasionally be red, violet, green or blue, often with a cream-coloured base layer.

Colonies growing under overhangs can develop elongations that become shaped like tear-drops, dangle on threads of tissue and eventually detach, landing on the seabed below and growing into new colonies; the sponge has also been observed to develop bubble-like buds on its external surface which become detached and, being buoyant, are dispersed by currents in the water column and rapidly grow into new colonies.

[4] Oscarella lobularis has been used as a model organism for the study of evolutionary biology and developmental biology, being particularly suitable because of its easy availability, its simple histology and cell composition, its robust epithelial structures and because it lacks a skeleton.