We study the flow around the Io flux tube by analyzing the eleven spectra taken by the Voyager 1 Plasma Science (PLS) experiment in its vicinity. We determine the bulk plasma parameters using a procedure that uses the full response function of the instrument and the data in all four PLS sensors. The mass density of the plasma in the vicinity of Io is found to be 22,500¿2500 amu/cm3, and its electron density is found to be 1500¿200 cm-3. We determine the Alfv¿n speed using three independent methods; the values obtained are consistent and, taken together, yield VA =300¿50 km/s, corresponding to an Alfv¿n Mach number of 0.19¿0.02. For the flow pattern we find good agreement with the model of Neubauer (1980) and conclude that the plasma flows around the flux tube with a pattern similar to the flow of an incompressible fluid around a long cylindrical obstacle of radius 1.26¿0.1 RIo.