Abstract The oxidation behavior of 316 stainless steel (SS) annealed in air containing 0.1 atm water vapor at temperatures ranging from 800 to 1030 °C was investigated. A kinetic study of the oxidation was made by employing thermal-gravimetric analysis (TGA). The morphology, composition and structure of the scale were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results showed that significant breakaway oxidation occurred, resulting in substantial weight increase, as the steel was annealed in moist air at temperatures above 950 °C. The scaling behavior of 316 SS in wet air at 1030 °C could be divided into two stages based on the alteration of the oxidation rate. In each stage, the scale on 316 SS exhibited a different structure and morphology. The complex process of the formation of scale in wet air was discussed and proposed.