Reaching a maximum overall length of 47 cm (19 in), P. waigiensis is of brownish to steel-grey colouration, sometimes with white vertical bars along the body.

With its typical centropomid body shape, it can be distinguished from the barramundi (Lates calcarifer) from the same waters by its widely set nostrils and shorter maxilla which does not reach back further than the eye (which is reddish).

[citation needed] The Waigeo "sea perch" occurs primarily among rocks and in coral reefs, preferring vegetated waters.

It is a nocturnal predator, feeding primarily on crustaceans and other fishes and hiding during the day.

The generic name Psammoperca derives from the Greek ψάμμος (sand) and πέρκη (perch).