This study evaluates the high-temperature oxidation and corrosion resistance of Inconel 617 (IN617) fabricated using the Wire Arc Additive Manufacturing (WAAM) process, with a focus on its performance under hot air and molten salt environments at 700 °C. The as-built microstructure exhibited columnar dendritic grains, with chromium- and molybdenum-rich interdendritic precipitates. Electron Backscatter Diffraction analysis revealed a strong ⟨001⟩ fiber texture with localized strain. WAAM-processed IN617 exhibited higher weight gain in molten salt (15.34 mg/cm2) compared to air (1.72 mg/cm2), attributed to salt-induced oxide growth at high temperatures. Oxidation in hot air formed a protective Cr2O3 and NiCr2O4 spinel phase. In contrast, exposure to a Na2SO4–60%V2O5 molten salt produced a porous, brittle oxide layer containing Ni3V2O8, Cr-V-O compounds, and sulfates, which caused severe scale breakdown, as confirmed by X-ray Photoelectron Spectroscopy (XPS). Parabolic rate constants indicated faster corrosion in molten salt (Kp = 5.16 × 10−10 g2.cm−4.s−1) than in air (Kp = 1.26 × 10−11 g2.cm−4.s−1). WAAM IN617 exhibits good oxidation resistance in air but is severely degraded in environments containing sodium, vanadium, and sulfur, particularly at high temperatures.