This paper presents a detailed experimental investigation on the effects of projectile hardness on the behaviour of thermoplastic composites under impact loading. In this research, gas-gun experiments employ gelatine and high-density polyethylene (HDPE) projectiles, of the same mass and diameter, to impact against woven carbon-fibre reinforced poly (ether-ether ketone) (CF/PEEK) composite specimens. During the experiments, a high-speed camera is employed to capture the deformation of the projectiles and a three-dimensional (3D) Digital Image Correlation (DIC) system is employed to record the major strain and out-of-plane displacement of the thermoplastic composite specimens. Experimental results, including the Digital Image Correlation (DIC) output and the post-impact status, are obtained and compared to show the effects of harder projectiles on increasing the impact damage. The composite specimens, impacted by gelatine and high-density polyethylene (HDPE) projectiles, presented similar major strain and out-of-plane displacement, but the high-density polyethylene (HDPE)-impacted composite specimens show more severe damage than the gelatine-impacted composite specimens.