A yellow-pigmented bacterial strain, originally designated 15-S14-6T, was isolated from the southern coastal waters of Korea and was subjected to taxonomic study using a polyphasic approach. Strain 15-S14-6T was Gram-staining-negative, flagellated, rod-shaped and aerobic. The strain grew optimally at 25-30 °C, in the presence of 2 % (w/v) NaCl and at pH 7.5-8.0. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that 15-S14-6T represented a member of the genus Mesonia and exhibited the highest sequence similarity (98.0 %) with Mesonia aquimarina IMCC1021T, followed by Mesonia mobilis KMM 6059T (96.7 %) and Mesonia phycicola MDSW-25T (96.1 %). DNA-DNA relatedness between 15-S14-6T and M. aquimarina IMCC1021T was 11.2±1.6 % (12.3±0.3 % in a reciprocal experiment). Strain 15-S14-6T had a DNA G+C content of 34.4 mol% and had MK-6 as the predominant menaquinone. Furthermore, iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 were identified as the major fatty acids. Phosphatidylethanolamine, two unknown aminolipids, an unknown phospholipid and four other unknown lipids were determined to be the major polar lipids. Based on phenotypic properties and phylogenetic data presented here, 15-S14-6T represents a novel species within the genus Mesonia , for which the name Mesonia maritima sp. nov. is proposed. The type strain is 15-S14-6T (= KCCM 43197T, NCAIM B.02633T, CGMCC 1.16020T).