Duplex Stainless Steels (DSS) are used in industrial sectors such as petrochemicals, nuclear and gas transport for their corrosion resistance and mechanical properties. Moreover, the presence of hydrogen could induce not only a modification in the fracture mechanisms (and so a ductile to brittle transition), but also changes in the plasticity mechanisms. However, the duplex microstructure (austenite and ferrite) of DSS constitutes a real difficulty in understanding their mechanical behavior in the presence of hydrogen. Indeed, it is at the scale of the microstructure that the effects must be investigated: accommodation of the plastic deformation by each of the two phases, interactions of the effects taking place in each phase. But one of the key points is the localization of hydrogen in the material and in particular at the level of the two phases. The hydrogen localization and quantification depend on the diffusion during the charging, and after on the solubility of hydrogen in each phase but also on the hydrogen trapping sites. The microstructure (grain size, phases distribution and orientation) is an influential factor. Moreover, the macroscopic techniques do not allow either to quantify the presence of hydrogen at the level of the microstructure of a duplex steel or to localize the hydrogen. Thus, the object of the present study is to show how KPFM (Kelvin Probe Force Microscopy) analyzes allow a better knowing and understanding of the hydrogen localization after the cathodic charging of a low duplex stainless steel DSS2304. For the studied steel, the austenitic phase which embeds in the ferritic matrix is in the form of elongated islands in the rolling direction. Hydrogen was introduced into the steel by using an electrochemical cell with a cathodic current density of 10 mA/cm2 in a 0.5M H2SO4 electrolyte containing 0.2 g/L As2O3 for different durations: 5 hours, 24 hours, 7 days. The hydrogen was charged perpendicularly to the rolling direction. MFM (Magnetic Force Microscopy) and KPFM have been carried out at the surface of the hydrogen charging samples but also for cross sections of these samples. The KPFM analyzes show the evolution of the surface potential with the presence of hydrogen. This depends on each phase and is more important for the ferrite. The KPFM analyses of the cross sections allow to estimate the penetration of hydrogen thickness into the steel. The austenite islands appear as barriers to the penetration of hydrogen into the thickness of the steel. The influence of a plastic deformation of the hydrogen penetration is studied by the used method and the effect of the microstructure on the hydrogen penetration and localization is discussed.