A novel actinomycetal strain, designated M600PL45_2^T, was isolated from marine sediments obtained from Ingleses beach, Porto, on the Northern Coast of Portugal and was subjected to a polyphasic taxonomic characterisation study. The here described Gram-reaction-positive strain is characterised by the production of a brown pigment in both solid and liquid medium and forms typical helical hyphae that differentiate into smooth spores. The results of a phylogenetic analysis based on the 16S rRNA gene sequence indicated that M600PL45_2^Thas a high similarity to two members of the genusStreptomyces,Streptomyces bathyalisASO4wet^T(98.51 %) andStreptomyces daqingensisNEAU ZJC8^T(98.44 %). The genome of M600PL45_2^Thas a size of 6 695 159 bp, a DNA G+C content of 70.71 mol% and 5538 coding sequences. M600PL45_2^Tgrows at 15–37 °C and with a maximal growth rate between 25 °C and 30 °C. Growth at pH 6.0 to 9.0 with the optimal range between 6.0 and 7.5 was observed. M600PL45_2^Tshowed a high salinity tolerance, growing with 0–10 % (w/v) NaCl, with best growth with 1–3% (w/v) NaCl. Major cellular fatty acids are iso-C_15:0(25.03 %), anteiso-C_15:0(17.70) and iso-C_16:0(26.90 %). The novel isolate was able to grow in media containing a variety of nitrogen and carbon sources. An antimicrobial activity screening indicated that an extract of M600PL45_2^Thas inhibitory activity againstStaphylococcus aureus. On the basis of the polyphasic data, M600PL45_2^T(= CECT 30365^T= DSM 114036^T) is introduced as the type strain of a novel species, that we namedStreptomyces marispadixsp. nov.