A Gram-stain-negative, non-spore-forming, aerobic, non-flagellated, gliding and rod-shaped bacterial strain, designated HJ-26M(T), was isolated from a tidal flat sediment in the Korean peninsula. It grew optimally at 25-30 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that the strain fell within the clade comprising Tenacibaculum species, clustering coherently with the type strains of Tenacibaculum lutimaris and Tenacibaculum aestuarii. Strain HJ-26M(T) exhibited the highest 16S rRNA gene sequence similarity values of 98.4 and 98.2 % to T. lutimaris TF-26(T) and T. aestuarii SMK-4(T), respectively, and of 94.9-97.4 % to the type strains of the other Tenacibaculum species. Strain HJ-26M(T) contained MK-6 as the predominant menaquinone and iso-C15:0 and iso-C17:0 3-OH as the major fatty acids. The DNA G+C content of strain HJ-26M(T) was 34.5 mol% and its mean DNA-DNA relatedness values with the type strains of T. lutimaris and T. aestuarii were 19 and 23 %, respectively. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain HJ-26M(T) is separate from other Tenacibaculum species. On the basis of the data presented, strain HJ-26M(T) is considered to represent a novel species of the genus Tenacibaculum, for which the name Tenacibaculum caenipelagi sp. nov. is proposed. The type strain is HJ-26M(T) (= KCTC 32323(T) = CECT 8283(T)).