A Gram-negative, aerobic, short rod-shaped bacterium, designated ASW11-19^T, was isolated from a coastal seawater sample of the Yellow Sea, PR China. Strain ASW11-19^T grew optimally at 37 °C, 3.0–5.0% (w/v) NaCl and pH 7.5. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain ASW11-19^T belonged to the genus Alteromonas and most closely related to Alteromonas profundi 345S023^T and Alteromonas fortis 1^T (98.4%, both). The draft genome was 3.55 Mb with 3150 protein-coding genes, 18 contigs, and a DNA G+C content was 44.4%. The digital DNA–DNA hybridization and average nucleotide identity values were below the species-delineating thresholds. The major fatty acids were summed feature 3 (C_16:1ω7c/C_16:1ω6c), summed feature 8 (C_18:1ω7c/C_18:1ω6c), and C_16:0. The sole respiratory quinone was ubiquinone 8. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phospholipid, and two unidentified lipids. Based on these genomic data, phenotypic and chemotaxonomic properties, strain ASW11-19^T is considered to represent a novel species of the genus Alteromonas. The name Alteromonas salexigens sp.nov. is proposed for ASW11-19^T (=MCCC 1K07239^T=KCTC 92247^T).