Tungsten oxide (WO3) thin films were prepared on Corning (CG) and Fluorine doped tin oxide (FTO) glass substrates at partial pressure of oxygen (pO2) 4 × 10−2 Pa and 8 × 10−2 Pa using DC magnetron sputtering (DCMs). In this work, we have varied the deposition parameters like pO2, target currents, and temperature. At pO2 4 × 10−2 Pa and 8 × 10−2 Pa samples were deposited at target currents of 50 mA and 100 mA, the maintained growth conditions are RT (substrate temperature 28 °C), Pre annealed (substrate temperature 400 °C), and Post annealed (annealing temperature 400 °C). The samples were systematically characterized for vibrational, structural, optical, and Electrochromic (EC) properties by using Raman, XRD, Uv-Vis spectrometer, and Electrochemical analyzer respectively. XRD analysis reveals that RT-deposited samples show amorphous nature and pre & post-annealed samples show a crystalline nature for both pO2. Optical transmittance was higher at RT-deposited samples at 50 mA (94% & 92%) and lower at 100 mA (87% & 85%) at the wavelength of 600 nm for both pO2. From CV analysis higher cathodic peak current density was observed in RT-deposited samples at 50 mA (−6.49 mAcm−2 & -13.80 mAcm−2) and lower at 100 mA (−5.25 mAcm−2 & -12.88 mAcm−2) for both pO2. The diffusion coefficient was observed at a higher target current at 100 mA (1.06 × 10−7 cm2/s & 9.20 × 10−8 cm2/s). For annealed samples optical and EC properties were decreased for both pO2.