Semiaquatic bugs (Hemiptera: Heteroptera: Gerromorpha) are predatory insects that occupy a wide range of freshwater and marine habitats, with some secondary transitions to terrestrial life. They currently represent more than 2100 species distributed through all continents, except for Antarctica, and are especially rich in the Neotropical and Oriental regions. Although the fauna from the former region is relatively well known, some areas remain almost unexplored. Such is the case of French Guiana, where only a few species have been previously recorded, several of which based on collections made in the 19 ^th and early 20 ^th centuries. As a result of material recently collected in the territory, the descriptions of Rhagoveliadepressa Rodrigues, Khila & Moreira, sp. nov., R.tantilloides Rodrigues, Khila & Moreira, sp. nov. and Steinoveliavittata Rodrigues, Khila & Moreira, sp. nov. (Veliidae) are presented here. New records for 28 species are also provided, of which Cylindrostethushungerfordi Drake & Harris, 1934, Neogerrismagnus (Kuitert, 1942), Rheumatobatesmangrovensis (China, 1943), R.trinitatis (China, 1943), Ovatametraobesa Kenaga, 1942, Telmatometrafusca Kenaga, 1941, T.parva Kenaga, 1941 (Gerridae), Mesoveliaamoena Uhler, 1894 (Mesoveliidae), Rhagoveliabrunae Magalhães & Moreira, 2016, R.elegans Uhler, 1894, R.ephydros (Drake & Van Doesburg, 1966), R.equatoria D. Polhemus, 1997, R.evidis Bacon, 1948, R.guianana D. Polhemus, 1997, R.tenuipes Champion, 1898, Oioveliacunucunumana (Drake & Maldonado-Capriles, 1952), Striduliveliaalia (Drake, 1957), S.stridulata (Hungerford, 1929), and S.tersa (Drake & Harris, 1941) (Veliidae) are reported from French Guiana for the first time.