A new giant clam species, Tridacna ningaloo Penny & Willan, 2014 has been described from Ningaloo Reef, Western Australia. Meanwhile, it has been suggested that Noah's giant clam, Tridacna noae (Röding, 1798), previously resurrected from synonymy with T. maxima (Röding, 1798), is an invalid name. We assessed the validity of resurrecting T. noae and designating a neotype for it against the rules of zoological nomenclature and found no flaw in these acts. We then compared the genetic and morphological characters used in the respective diagnoses of T. noae and the newly-described Tridacna ningaloo. No difference was apparent between T. ningaloo and T. noae except, possibly, in mantle ornamentation patterns. In particular, the holotype of T. ningaloo possesses a mitochondrial DNA haplotype identical to T. noae. Thus, the hypothesis that T. ningaloo is a species distinct from T. noae was not supported by clear morphological evidence and it was contradicted by the available genetic evidence. Tridacna ningaloo should be regarded as a junior synonym of T. noae.