One of the hypothetical accidents studied in the field of the safety studies of Pressurized light Water Reactors (PWR) is the Loss-Of-Coolant Accident (LOCA). In this scenario, zirconium alloy fuel claddings could undergo a high level of oxidation at high temperature in a steam environment. Cladding tubes constitute the first confinement barrier of radioelements and then it is essential that they keep a certain level of ductility after quenching to ensure their integrity. These properties are directly related to the growth kinetics of both the oxide and the sub-oxide αZr(O) layers and especially to the oxygen diffusion profiles in the residual prior-β layer after HT oxidation and final water quenching. This study was focused on the influence of a pre-annealing thermal treatment performed on first generation of 6-8 µm thick Cr-coated zirconium based specimens and on their further HT oxidation behavior. The effect of pre-annealing temperature on the structure and morphology of the Chromium coating microstructure was investigated using scanning electron microscopy. During the annealing treatment, the chromium coating experienced recrystallisation and the initial columnar grains morphology became more equiaxed. After oxidation at HT, the weight gains of pre-annealed Cr-coated specimen were generally lower than the non-annealed ones. Glow discharge mass spectrometry, Electron Probe Micro Analysis and Raman spectroscopy measurements have confirmed that the thickness of ZrO2 and αZr(O) phases were significantly reduced for some of the pre-annealed samples, indicating that the grain size and morphological evolutions of the chromium coating upon the pre-annealing thermal treatment may influence its further HT oxidation behavior.