A novel Gram-stain-negative, aerobic, rod-shaped, non-flagellated, and gliding bacterial strain, designated DF109(T), was isolated from the coastal sediment of Jingzi Wharf, Weihai, China. The optimal growth occurs at 28 degrees C, pH 7.0-7.5, and 1.0% (w/v) NaCl environment. The colony was yellow-colored, convex, non-transparent, and circular on 2216E Agar. Phylogenetic analyses of the 16S rRNA gene and genome sequence of this newly isolated strain revealed that it is a member of the genus Gelidibacter within the family Flavobacteriaceae. The phylogenetic analysis based on 16S rRNA gene sequences indicated that strain DF109(T) has the highest sequence similarity to Gelidibacter japonicus JCM 31967(T) (98.0%). The average nucleotide identity (ANI) values between genomes of DF109(T) and G. japonicus JCM 31967(T) and G. algens DSM 12408(T) were 86.3% and 78.7% and the digital DNA-DNA hybridization (dDDH) values were 31.4% and 22.4%, respectively. The sole isoprenoid quinone was MK-6 and the major cellular fatty acids were iso-C(15:1)G, iso-C-17:0 3-OH, anteiso-C-15:0, and iso-C-16:0 3-OH. The major polar lipids of strain DF109(T) were an aminolipid, a phosphatidylethanolamine, and four unidentified lipids. The genomic DNA G+C content was 37.5 mol%. Strain DF109(T) is suggested to represent a novel species in the genus Gelidibacter, for which the name Gelidibacter pelagius sp. nov. is proposed. The type strain is DF109(T) (=MCCC 1H00454(T)=KCTC 82420(T)).