Thirteen novel planctomycetal strains were isolated from five different aquatic sampling locations. These comprise the hydrothermal vent system close to Panarea Island (Italy), a biofilm on the surface of kelp at Monterey Bay (CA, USA), sediment and algae on Mallorca Island (Spain) and Helgoland Island (Germany), as well as a seawater aquarium in Braunschweig, Germany. All strains were shown to belong to the genus Gimesia . Their genomes cover a size range from 7.22 to 8.29 Mb and have a G+C content between 45.1 and 53.7%. All strains are mesophilic (T opt 26–33 °C) with generation times between 12 and 32 h. Analysis of fatty acids yielded palmitic acid (16:0) and a fatty acid with the equivalent chain length of 15.817 as major compounds. While five of the novel strains belong to the already described species Gimesia maris and Gimesia chilikensis , the other strains belong to novel species, for which we propose the names Gimesia alba (type strain Pan241w T = DSM 100744 T = LMG 31345 T = CECT 9841 T = VKM B-3430 T ), Gimesia algae (type strain Pan161 T = CECT 30192 T = STH00943 T = LMG 29130 T ), Gimesia aquarii (type strain V144 T = DSM 101710 T = VKM B-3433 T ), Gimesia fumaroli (type strain Enr17 T = DSM 100710 T = VKM B-3429 T ) and Gimesia panareensis (type strain Enr10 T = DSM 100416 T = LMG 29082 T ). STH numbers refer to the Jena Microbial Resource Collection (JMRC).