This study of species diversity of the subfamily Papilionoideae in southern Thailand was carried out from September 2017 to December 2019 and it included both the study of fresh specimens and of herbarium collections. Sixty-three genera, 199 species, three subspecies and five varieties were encountered. The most diverse genus was Crotalaria with 19 species. The study found five endemics, five new species records, three species that were expected new records or new species, 13 threatened species, 13 species that had not been previous recorded for southern Thailand, nine species which occur naturally in other regions and which had been introduced to southern Thailand and  finally 33 exotic species. Here we provide an updated checklist with information on plant habits, habitats, flowering–fruiting periods and provincial distributions.