Four spirochetes (F1^T, B21, Yale^T and AMB6-RJ) were isolated from environmental sources: F1^T and B21 from soils of an urban slum community in Salvador (Brazil), Yale^T from river water in New Haven, Connecticut (USA) and AMB6-RJ from a pond in a horse farm in Rio de Janeiro (Brazil). Isolates were helix-shaped, aerobic, highly motile and non-virulent in a hamster model of infection. Draft genomes of the strains were obtained and analysed to determine the relatedness to other species of the genus Leptospira . The analysis of 498 core genes showed that strains F1^T/B21 and Yale^T/AMB6-RJ formed two distinct phylogenetic clades within the ‘Pathogens’ group (group I). The average nucleotide identity (ANI) values of strains F1^T/B21 and Yale^T/AMB6-RJ to other previously described Leptospira species were below <84 % and <82 %, respectively, which confirmed that these isolates should be classified as representatives of two novel species. Therefore, we propose Leptospira yasudae sp. nov. and Leptospira stimsonii sp. nov. as new species in the genus Leptospira . The type strains are F1^T (=ATCC-TSD-163=KIT0259=CLEP00287) and Yale^T (=ATCC-TDS-162=KIT0258=CLEP00288), respectively.