This paper presents a preliminary assessment on the oceanographic and biogeochemical characteristics of the Tavares River (ERT) and Defuntos River (ERD) estuaries, located in the Limões Bight, Pirajubaé Extractivist Reserve, Florianópolis, SC. Field surveys were carried out in the estuaries at June 30th on July 1st, 2000, along complete tidal cycles, 13 hours, under spring tide condition. At every survey the follow parameters were monitored: current speed and direction, salinity, temperature, particulate suspended matter (PSM), pH, dissolved oxygen, and inorganic dissolved nutrients concentration (ammonium, nitrite, nitrate, phosphate and silicon). In spite of being close one another less than 1 km, the estuaries showed considerably differences in the intra-tidal variation of the monitored parameters. The parameters in the ERT showed good coherence with flood and ebb tidal phases, meanwhile in the ERD they showed more complex pattern. In terms of net transport, the ERT exports PSM and nutrients towards Limões bight, and the ERD imports PSM though exports nutrients. Beside the major influence of the astronomical semi-diurnal tide, seiches are also important to these estuaries. The main seiches periods ranged between 1 and 2 hours.