Echyridella onekaka is a species of freshwater mussel endemic to New Zealand.

E. onekaka is an aquatic bivalve mollusc in the family Unionidae, the river mussels.

It can be distinguished from Echyridella menziesii by a more strongly separated anterior pedal retractor muscle.

[2] Echyridella onekaka is found exclusively in the north-west of the South Island.

[4] It is the rarest known freshwater mussel species in New Zealand.