As energy consumption increases globally and environmental issues threaten the quality of life, new sustainable ways of energy generation are being actively researched and promoted. Although offshore wind energy has demonstrated great potential, the costs need to be significantly reduced in order to compete with conventional energy types. The aim of this project is to investigate the structural design and performance of a floating offshore wind turbine (FOWT) foundation and solutions to its cost reduction. The floating foundation will be designed based on a number of well recognised design guidelines, including DNV GL, Eurocode, etc. The dynamic response and structural performance including fatigue performance of FOWT foundation will be investigated by using finite element analysis. The structural reliability will be assessed to reduce malfunctions, failures and accidents.