The study deals with the ‘vanadium (IV) sulfate’ and ‘vanadium (V) pentoxide’ dissolution processes in 3 M H2SO4 aqueous media. Several measurements of the concentration of dissolved VO2+ and VO2+ were achieved in the range of 0–40 °C, and allowed to understand the limitations of the dissolution process (‘endothermic’ – mass transport for VOSO4 and ‘exothermic’ – reaction with the proton for V2O5). In addition, simple models were proposed (diffusion/accumulation for VOSO4 and kinetic rate for V2O5) and their resolution leads to theoretical kinetic equations describing the temporal evolution of these concentrations with satisfactory agreement with the experimental curves. Solubility’s data and their temperature dependence were determined for both vanadium compounds involved.