A floating offshore wind turbine (FOWT) is a coupled system where a wind turbine with flexible blades interacts with a moored platform in wind and waves. This paper presents a high-fidelity aero-hydro-mooring-elastic analysis tool developed for FOWT applications. A fully coupled analysis is carried out for an OC4 semi-submersible FOWT under a combined wind/wave condition. Responses of the FOWT are investigated in terms of platform hydrodynamics, mooring dynamics, wind turbine aerodynamics and blade structural dynamics. Interactions between the FOWT and fluid flow are also analysed by visualising results obtained via the CFD approach. Through this work, the capabilities of the tool developed are demonstrated and impacts of different parts of...