Strain LLG6346-3.1 T , isolated from the thallus of the brown alga Ericaria zosteroides collected from the Mediterranean Sea near Bastia in Corsica, France, was characterised using a polyphasic method. Cells were Gram-stain-negative, strictly aerobic, non-flagellated, motile by gliding, rod-shaped and grew optimally at 30–33 °C, at pH 8–8.5 and with 4–5 % NaCl. LLG6346-3.1 T used the seaweed polysaccharide alginic acid as a sole carbon source which was vigorously liquefied. The results of phylogenetic analyses indicated that the bacterium is affiliated to the genus Zobellia (family Flavobacteriaceae , class Flavobacteriia ). LLG6346-3.1 T exhibited 16S rRNA gene sequence similarity values of 98.6 and 98.3 % to the type strains of Zobellia russellii and Zobellia roscoffensis , respectively, and of 97.4–98.5 % to members of other species of the genus Zobellia . The DNA G+C content of LLG6346-3.1 T was determined to be 38.3 mol%. Digital DNA–DNA hybridisation predictions by the average nucleotide identity (ANI) and genome to genome distance calculator (GGDC) methods between LLG6346-3.1 T and other members of the genus Zobellia showed values of 76–88 % and below 37 %, respectively. The results of phenotypic, phylogenetic and genomic analyses indicate that LLG6346-3.1 T is distinct from species of the genus Zobellia with validly published names and that it represents a novel species of the genus Zobellia , for which the name Zobellia alginiliquefaciens sp. nov. is proposed. The type strain is LLG6346-3.1 T (= RCC7657 T = LMG 32918 T ).