This study evaluates the structural feasibility of a prismatic pressure vessel using strength assessments. A prismatic pressure vessel, which differs from a cylindrical or spherical pressure vessel, is proposed. A prismatic pressure vessel can be used to ship liquefied gas. A prototype of the prismatic pressure vessel was designed, manufactured and tested in accordance with the ASME Boiler and Pressure Vessel Code. Its design uses the "design-by-analysis" method, including protection against plastic collapse. The prototype of the prismatic pressure vessel uses typical construction materials considering their linear elastic and nonlinear plastic behaviors. The vulnerable components of the structure were obtained through numerical analysis using the finite element method. A pressure test with strain gauges was conducted, and the results demonstrate the feasibility of the prismatic pressure vessel as a suitable vessel for high-pressure fluids with high volume efficiencies. The prismatic pressure vessel has potential for general applicability in the shipping of liquefied gas.