Two Gram-stain-negative, non-spore-forming, rod-shaped, aerobic and yellow-coloured bacterial strains, designated strains ECD14T and EC2D5T, were isolated from a seaweed Eckloniacava. The isolates required sea salts for growth. Flexirubin-type and carotenoid pigment was produced. The 16S rRNA gene sequence similarity between the two new strains was 95.5 %. Flavivirga amylovorans JC2681T was the nearest neighbour of strains ECD14T and EC2D5T with 96.5 and 96.8 % 16S rRNA gene sequence similarity, respectively. The common major fatty acids and respiratory quinones were iso-C15 : 0, iso-C15 : 1 G and unknown 13.565 and menaquinone 6 (MK-6), respectively. The common major polar lipids were phosphatidylethanolamine, an unknown amino lipid and an unknown lipid. The DNA G+C contents of strains ECD14T and EC2D5T were 33 and 31 mol%, respectively. On the basis of the polyphasic characterization of the two strains, it is suggested that the two isolates represent novel species of the genus Flavivirga, for which the names Flavivirga eckloniae sp. nov. (type strain, ECD14T=KCTC 52352T=JCM 31797T) and Flavivirga aquimarina sp. nov. (type strain, EC2D5T=KCTC 52353T=JCM 31796T) are proposed.