Diunatans is an extinct genus of rorqual. It lived in the North Sea during the Early Pliocene. Two specimens have been found from the Netherlands. They were collected from the Kattendijk Formation in the province of Zeeland, which is Zanclean in age. Diunatans is considered to be a stem balaenopterid because it falls outside the Balaenoptera+Megaptera clade, which includes all living rorquals.