Methane gas is introduced into the steam microwave plasma, which is stabilized by a swirl flow. The steam microwave plasma provides highly active species and a high-temperature plasma flame, enhancing the chemical reaction rate and eliminating the need for catalysts. We investigated the dependence of the hydrogen concentration on the steam to carbon ratio at a given plasma power. Using a specially designed plasma nozzle, we achieved high hydrogen concentrations (>70 vol.%) in the effluent streams.