The recently developed Integral Hydro-Bulge Forming process (IHBF) was utilized in the manufacturing of single and multi-layered spherical pressure vessels and storage tanks. Single layer spherical vessels of 2-mm thickness and diameters of 31.65, 63.41, and 95.32 cm were manufactured. As an alternative means of manufacturing thick-walled spherical pressure vessels, the IHBF procedure was modified and used in forming of a double-layered composite pressure vessels with an effective thickness of 15 mm. The results indicated that the modified IHBF process may successfully be applied in the manufacturing of multi-layered spherical vessels of various thicknesses and diameters. In this paper, the conventional and modified IHBF procedure will be discussed and the experimental results and analysis will be presented.