Special two-chamber setups are used to study the formation of xenon hydrates from a vapor–gas medium, depending on the volume of the chamber. The effect different parameters have on the growth of hydrates and the degree of saturation is studied. Hydrate growth conditions with saturation indices close to ideal are determined. Based on the experimental data, an estimate is made of the size of the crystalline hydrate nucleus (minimum size, 10–15 µm). It is established that for the emergence of such a nucleus from a vapor–gas medium, the required amount of steam at a temperature of 5°C is contained in a sphere 1 cm in diameter. Conditions are determined for the growth of a hydrate with saturation close to theoretical from a vapor–gas medium. It is shown that the rate of hydrate formation in a vapor–gas medium is several orders of magnitude higher than the one for liquid water. Raising the initial temperature of the vapor–gas medium increases both the rate of hydrate formation and the proportion of such hydrate.