Cathodic protection, when used in conjunction with protective coatings, is a common method used to protect immersed parts of steel surfaces from corrosion. This text offers detailed recommendations on cathodic protection for offshore structures. Traditional seagoing vessels dock at regular intervals, but offshore structures such as Floating Production Storage and Offloading structures (FPSOs) are stationary and are in continuous operation for prolonged periods of time. Therefore, the design of the corrosion protection for a 15-year or longer service life of a floating offshore structure requires special consideration. Some Floating Production Installations (FPIs) have hull designs similar to oil tankers, especially those converted from oil tankers. Others are designed and built as floating production platforms. Cathodic protection systems are to consider the structure to be protected as a whole as well as individual components which are attached to the structure. The information presented in the text is intended solely to assist the reader in the methodologies and/or techniques discussed. This text does not and cannot replace the analysis and/or advice of a qualified professional. It is the responsibility of the reader to perform their own assessment and obtain professional advice. Information contained in this text is considered to be pertinent at the time of publication but may be invalidated as a result of subsequent legislation, regulations, standards, methods, and/or more updated information and the reader assumes full responsibility for compliance.