Strains J15B81-2 T and J15B91 T were isolated from a sediment sample collected from the South China Sea. Cells of both strains were observed to be rod-shaped, non-gliding, Gram-stain-negative, yellow-pigmented, facultatively anaerobic, catalase-positive, oxidase-negative and showing optimum growth at 30 °C. Strains J15B81-2 T and J15B91 T could tolerate up to 9 and 10  % (w/v) NaCl concentration and grow at pH 6.5–9.5 and 6.0–9.0, respectively. The strains shared 97.4 % 16S rRNA gene sequence similarity to each other but were identified as two distinct species based on 81.1–85.8 % ANIb and 31.5 % dDDH values calculated using whole genome sequences. Strains J15B81-2 T and J15B91 T shared highest 16S rRNA gene sequence similarity to Salinimicrobium xinjiangense CGMCC 1.12522 T (98.4 %) and Salinimicrobium sediminis CGMCC 1.12641 T (98.0 %), respectively. Among species with validly published names, S. sediminis CGMCC 1.12641 T shared close genetic relatedness with strains J15B81-2 T 85.1–85.3% average nucleotide identity based on blastBlast + (ANIb) and 30.6 % digital DNA–DNA hybridization (dDDH) and J15B91 T (76.6–79.1 % ANIb and 21.5 % dDDH). The major fatty acid of strains J15B81-2 T and J15B91 T were identified as iso-C 15 : 0 and iso-C 16 : 0 , respectively, and the major polar lipids of the two strains consisted of phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid and one unidentified lipid. The strains contained MK-6 as their predominant menaquinone. The genomic G+C contents of strains J15B81-2 T and J15B91 T were determined to be 41.7 and 41.8 mol %, respectively. Both strains are considered to represent two novel species of the genus Salinimicrobium and the names Salinimicrobium nanhaiense sp. nov. and Salinimicrobium oceani sp. nov. are proposed for strains J15B81-2 T (=KCTC 72867 T =MCCC 1H00410 T ) and J15B91 T (=KCTC 72869 T =MCCC 1H00411 T ), respectively.