Small size, high corrosion resistance, harsh environment compatibility, multiplexing capability, interrogation over large distances and EMI interference immunity make fiber optic systems ideal candidates for corrosion sensing. In this paper, a new sensor is proposed to efficiently gather crucial information on corrosion phenomena and their progression within steel components. Fabricated with plastic optical fibers (POF), the sensor can detect corrosion-induced physical changes in the appearance of monitoring points. developed based on a pressure-driven Fabry-P ́erot cavity (FPC). The POF sensor. In this study, a fiber optic sensing system based on long period fiber gratings (LPFG) in LP06 and LP07 modes is designed, fabricated and tested for simultaneous measurements of strain, temperature and corrosion-induced mass loss.