Plebidonax deltoides (previously Donax deltoides) is a small, edible saltwater clam or marine bivalve mollusc of the family Donacidae, endemic to Australia. It is most widely known as the pipi in the eastern states of its native Australia, and as the Goolwa cockle or Coorong cockle in South Australia; in south-eastern Queensland, it is often also known as eugarie or (y)ugari, a borrowing from the local Yugarabul language. This species should not be confused with the bivalve Paphies australis (of the family Mesodesmatidae), endemic to New Zealand and also called "pipi".