This paper investigates the potential application of Na-beta-alumina and silica gel electrolyte containing various phosphorates for steel protection under environmental conditions where no any other continuous ion conducting materials would exist on the steel surface. The experimental results showed that the open circuit potential of the steel/solid electrolyte interface versus the platinum reference electrode originated from the corrosion of steel by oxygen gas and water that penetrated through the electrolytes. It was revealed that the cathodic and anodic polarization behaviour of steel was affected by factors such as the nature of electrolyte, the temperature and the relative humidity. Effective cathodic protection has been demonstrated, with some indications of the change at the steel/solid electrolyte interface provided by complex impedance analyses.