Wire Arc Additive Manufacturing (WAAM) has emerged as an innovative technology for producing large-scale components, offering substantial benefits in reducing material waste and production time for complex geometries. However, the unique layered microstructure and inherent material characteristics of WAAM-fabricated components introduce a need for a better understanding of mechanical behaviours, particularly in ductile fracture under multiaxial stress conditions. Understanding these fracture mechanisms is crucial for optimising structural designs, yet knowledge in this area remains limited. Ductile fracture behaviour, influenced by stress states, strain localisation, and microstructural heterogeneities, is a crucial factor in predicting the structural integrity and reliability of WAAM materials. Accurate fracture prediction requires determinations of fracture strain and stress conditions via comprehensive coupon tests and advanced finite element (FE) analysis. This study aims to systematically investigate the ductile fracture properties of WAAMfabricated materials using S690 equivalent wire, focusing on mechanical response, stress state conditions, and the influence of the as-built condition. Experimental methods include tensile testing of different triaxial conditions to capture the variety of fracture modes, supported by high-resolution imaging techniques to analyse microstructural features. Additionally, FE modelling will be employed to simulate fracture behaviour and validate experimental findings, providing insights into the unique failure characteristics of WAAM structures. The results of this research are expected to improve fracture prediction models and yield practical recommendations for incorporating WAAM-specific properties into FE simulations, ultimately enhancing design and performance reliability for WAAM-fabricated components in demanding structural applications.