Eleven bacterial strains were isolated from freshwater environments and identified as Flavobacterium based on 16S rRNA gene sequence analyses. Complete genome sequences of the 11 strains ranged from 3.45 to 5.83 Mb with G + C contents of 33.41–37.31%. The average nucleotide identity (ANI) values showed that strains IMCC34515T and IMCC34518 belonged to the same species, while the other nine strains represented each separate species. The ANI values between the strains and their closest Flavobacterium species exhibited ≤ 91.76%, indicating they represent each novel species. All strains had similar characteristics such as being Gram-stain-negative, rod-shaped, and contained iso-C15:0 as the predominant fatty acid, menaquinone-6 as the respiratory quinone, and phosphatidylethanolamine and aminolipids as major polar lipids. Genomic, phylogenetic, and phenotypic characterization confirmed that the 11 strains were distinct from previously recognized Flavobacterium species. Therefore, Flavobacterium praedii sp. nov. (IMCC34515T = KACC 22282T = NBRC 114937T), Flavobacterium marginilacus sp. nov. (IMCC34673T = KACC 22284T = NBRC 114940T), Flavobacterium aestivum sp. nov. (IMCC34774T = KACC 22285T = NBRC 114941T), Flavobacterium flavigenum sp. nov. (IMCC34775T = KACC22286T = NBRC 114942T), Flavobacterium luteolum sp. nov. (IMCC34776T = KACC 22287T = NBRC 114943T), Flavobacterium gelatinilyticum sp. nov. (IMCC34777T = KACC 22288T = NBRC 114944T), Flavobacterium aquiphilum sp.nov. (IMCC34779T = KACC 22289T = NBRC 114945T), Flavobacterium limnophilum sp. nov. (IMCC36791T = KACC22290T = NBRC 114947T), Flavobacterium lacustre sp. nov. (IMCC36792T = KACC 22291T = NBRC 114948T), and Flavobacterium eburneipallidum sp. nov. (IMCC36793T = KACC 22292T = NBRC 114949T) are proposed as novel species.