Two bacterial strains (DY05T and 47666-1) were isolated in Queensland, Australia, from diseased cultured crustaceans Panulirus ornatus and Penaeus monodon, respectively. On the basis of 16S rRNA gene sequence identity, the strains were shown to belong to the Harveyi clade of the genus Vibrio. Multilocus sequence analysis using five housekeeping genes (rpoA, pyrH, topA, ftsZ and mreB) showed that the strains form a monophyletic group with 94.4% concatenated sequence identity to the closest species. DNA–DNA hybridization experiments showed that strains DY05T and 47666-1 had 76% DNA similarity to each other, but <70% to their closest neighbours Vibrio harveyi LMG 4044T (≤55%), Vibrio campbellii LMG 11216T (≤52%) and Vibrio rotiferianus LMG 21460T (≤46%). Strains DY05T and 47666-1 could be differentiated from their relatives on the basis of several phenotypic characteristics. The major fatty acids were C15:0 iso 2-OH and/or C16:1ω7, C16:0, C18:1ω7 and C14:0. Based on the polyphasic evidence presented here, it can be concluded that strains DY05T and 47666-1 belong to the same novel species of the genus Vibrio, for which the name Vibrio owensii sp. nov. is proposed. The type strain is DY05T (=JCM 16517T=ACM 5300T).