Two Gram-negative, facultatively anaerobic, rod-shaped bacteria, strains EF212(T) and PS125(T), were isolated from the octocorals Eunicea fusca and Plexaura sp., respectively. EF212(T) was isolated from a specimen of E. fusca collected off the coast of Florida, USA, and PS125(T) was isolated from a specimen of Plexaura sp. collected off the coast of Bimini, Bahamas. Analysis of the nearly full-length 16S rRNA gene sequences showed that these novel strains were most closely related to Endozoicomonas montiporae CL-33(T), E. elysicola MKT110(T) and E. numazuensis HC50(T) (EF212(T), 95.6-97.2 % identity; PS125(T), 95.1-96.4 % identity). DNA-DNA hybridization values among EF212(T), PS125(T), E. montiporae LMG 24815(T) and E. elysicola KCTC 12372(T) were far below the 70 % cut-off, with all values for duplicate measurements being less than 35 %. Both EF212(T) and PS125(T) required NaCl for growth and showed optimal growth at 2-3 % NaCl, 22-30 °C and pH 8.0. The predominant cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c), C16 : 0 and C14 : 0. The DNA G+C content of EF212(T) was 48.6 mol% and that of PS125(T) was 47.5 mol%. In addition to the genotypic differences observed between the two novel strains and related type strains, phenotypic and chemotaxonomic experiments also revealed differences between strains. Thus, strains EF212(T) and PS125(T) represent novel species of the genus Endozoicomonas, for which the names Endozoicomonas euniceicola sp. nov. and Endozoicomonas gorgoniicola sp. nov., respectively, are proposed. The type strains are EF212(T) ( = NCCB 100458(T) = DSM 26535(T)) for Endozoicomonas euniceicola sp. nov. and PS125(T) ( = NCCB 100438(T) = CECT 8353(T)) for Endozoicomonas gorgoniicola sp. nov. An emended description of the genus Endozoicomonas is also provided to encompass differences observed in the results of genotypic, chemotaxonomic and phenotypic tests compared from the original and amended genus descriptions.