Corrosion behavior of a protective insulated coating (PIC) on 304 stainless steel (SS) surfaces was investigated in high temperature water under various water chemistry conditions by measuring the electrochemical corrosion potential (ECP) and flow-assisted corrosion (FAC) rate.  The ECP results clearly demonstrate that the PIC layer restricted oxidant transport to the metal surface, and the ECP remained at <-230 mV(SHE) in 288^oC containing high oxygen (O₂) and no hydrogen (H₂).  In this paper, long term durability of PIC layer prepared by various coating methods will be discussed.