Two new species of Floresorchestia (Crustacea: Amphipoda) are described from Amphawa Estuary, Samut Songkhram Province, Thailand. Floresorchestia amphawaensis sp. nov. is a riparian-hoppers living near agricultural and urban areas, being distinguished by the following character states: left mandible lacinia mobilis 4-dentate; gnathopod 2 palm reaching about 34%; telson as broad as long, with four robust setae per lobe. Floresorchestia pongrati sp. nov. are described as riparian-hoppers living in the moist area near Mae Klong canal banks with a unique left mandible lacinia mobilis 5-dentate; gnathopod 2 palm reaching 30% and telson with seven robust setae per lobe. The status and the problem of diagnostic character states of the genus Floresorchestia are discussed.