A Gram-stain-negative, non-spore-forming, aerobic, motile, ovoid or rod-shaped bacterium, designated strain C34T, was isolated from a Porites species coral on Weizhou Island, China. Optimal growth occurred in 4 % NaCl (w/v), at 30 °C and pH 8. The only detected respiratory quinone was Q-8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified ninhydrin-positive lipids, one ninhydrin-positive unidentified phospholipid and two unidentified polar lipids. The genome DNA G+C content was 56.7 mol%. The major cellular fatty acids were C16 : 1ω7c/iso-C15 : 0 2-OH, C16 : 0, C18 : 1ω7c/ω6c, C18 : 0 and iso-C11 : 0 3-OH. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain C34T forms a stable cluster with Motiliproteus sediminis CICC 10858T (with the highest sequence similarity of 95.7 %). Strain C34T was also physiologically and chemical taxonomically similar to M. sediminis CICC 10858T, although they could be distinguished by colony colour on 2216E agar, the flagellum position and the diphosphatidylglycerol content in the cellular polar lipid. Thus, strain C34T is suggested to represent a new species in the genus Motiliproteus, for which the name Motiliproteus coralliicola is proposed. The type strain is C34T (=MCCC 1K03462T=KCTC 62319T).