A Gram-stain-negative, aerobic, chemoheterotrophic, rod-shaped bacterium motile by a polar flagellum, designated IMCC34675(T), was isolated from Chungju Lake, an artificial freshwater reservoir in Republic of Korea. The 16S rRNA gene sequence analysis indicated that strain IMCC34675(T) belongs to the genus Uliginosibacterium, sharing <= 97.1% sequence similarities with the type strains of the genus. Whole genome sequencing of strain IMCC34675(T) revealed a 4.1 Mbp of genome size with 62.4% of the DNA G + C content. The IMCC34675(T) genome shared 73.3% of average nucleotide identity and 19.9% of digital DNA-DNA hybridization values to the genome of Uliginosibacterium gangwonense DSM 18521(T), the type species of the genus. The major fatty acids of strain IMCC34675(T) were summed feature 3 (comprising C-16:1 omega 6c and/or C-16:1 omega 7c) and C-16:0. The respiratory quinone detected in the strains was ubiquinone-8 (Q-8). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminophospholipid, one aminolipid, and five unidentified lipids. Based on the phylogenetic and phenotypic characterization, strain IMCC34675(T) was considered to represent a novel species within the genus Uliginosibacterium, for which the name Uliginosibacterium aquaticum sp. nov. is proposed with IMCC34675(T) (= KACC 21758(T) = NBRC 114418(T)) as the type strain.