Wire and Arc Additive Manufacturing (WAAM) is, nowadays, one of the most relevant Additive Manufacturing (AM) processes, used to produce large-scale metal parts. It is an Arc-based Directed Energy Deposition (DED-arc) process, based on conventional metal inert/active gas welding (MIG/MAG). The main advantages of WAAM are the high deposition rates, its affordability, and the wide feedstock availability. However, it is susceptible to stochastic phenomena that may lead to defect formation, such as porosities, lack of fusion, cracking, and microstructure heterogeneities. The inline inspection of WAAM parts is highly demanding due to the non-flat surfaces, high waviness and roughness, small-size defects, and high temperature. The objective of this work was to develop customized NDT techniques, based on ultrasound (US) and eddy currents (EC) to improve the reliability of inline inspection of WAAM fabricated parts. Different US and EC probes were designed and adapted to the geometry of the deposited layers. Probes were numerically simulated, produced, and experimentally validated on WAAM samples of AWS ER-90s and AISI 316L steel, Inconel 625, and aluminium alloys. A dedicated inspection system was also developed to clean and inspect the wire feedstock material, since it can also be a source of defects or microstructure heterogeneities. Both conventional WAAM and In-situ hot forging WAAM were used to produce samples with artificial and real defects encompassing the most common defects morphology in WAAM. The experimental results confirmed the high difficulty in detecting such defects but showed an improvement in defects detection and SNR compared to conventional probes. The system for inspecting wire feedstock material, based on customized differential EC probes, was able to detect microstructural heterogeneities, surface oxide heterogeneities, and transversal section changes of wires.