This work is part of the DIGIFLOAT project. This project aims to provide a digital twin software framework that enables high-fidelity structural integrity analysis for a floating offshore wind turbine (FOWT) in its as-is state — we refer to this as a structural digital twin (SDT). The same framework is also applicable at design time to assess an extensive range of operational conditions with high-fidelity analysis. In order to achieve this purpose, we validate in this work, a complete system-level FOWT structural analysis framework, which is integrated with NREL OpenFAST and Akselos’ Integra® software. OpenFAST provides the global motions and loads, and these are mapped in the time-domain to the structural model for structural analysis. The structural analysis includes all relevant loads from the system-level model: wind turbine aerodynamics, hydrodynamics, servo-control, and mooring. We demonstrate that the Reduced Basis Finite Element Analysis (RB-FEA) used in Integra® makes detailed structural analysis of FOWT hulls efficient, and that this is an enabler for FOWT SDTs.