A Gram-negative, non-motile, non-gliding, strictly aerobic, pale yellow colony-forming, rod-shaped bacterial strain, designated HM0024(T), was isolated from coastal seawater of the Yellow Sea and subjected to a polyphasic taxonomy study. Based on 16S rRNA gene sequence similarities, strain HM0024(T) was most closely related to Chryseobacterium balustinum LMG 8329(T) (94.4 %), Chryseobacterium scophthalmum LMG 13028(T) (94.4 %), Chryseobacterium piscium LMG 23089(T) (94.3 %) and Elizabethkingia meningoseptica ATCC 13253(T) (94.0 %) and shared less than 92 % sequence similarity with other members of the family Flavobacteriaceae. Phylogenetic analyses showed that strain HM0024(T) formed an independent phyletic line of descent within the family Flavobacteriaceae. The DNA G+C content of the strain was 29.6 mol% and its major cellular fatty acids (>10 %) were iso-C(15 : 0), iso-C(17 : 0) 3-OH, iso-C(17 : 1)ω 7c and summed feature 3 (C(16 : 1)ω 6c and/or C(16 : 1)ω 7c). The major isoprenoid quinone was MK-6 and the major polar lipids were phosphatidylethanolamine and several aminolipids. Strain HM0024(T) was differentiated from phylogenetically related members of the family by having lower DNA G+C content, larger proportions of summed feature 3, anteiso-C(15 : 0) and iso-C(16 : 0) 3-OH and particular phenotypic characteristics. On the basis of phenotypic and phylogenetic data, strain HM0024(T) is classified as a representative of a novel genus and species, for which the name Soonwooa buanensis gen. nov., sp. nov. is proposed. The type strain of Soonwooa buanensis is HM0024(T) (=KCTC 22689(T) =CECT 7503(T)).