The Liquefied Natural Gas industry was developed to link huge gas reserves that occur in geographically remote countries to regions in need of natural gas as an energy resource. A great fraction of liquefied gases are light hydrocarbons and the key property that makes hydrocarbons the world s primary energy source is their flammability which, at the same time, makes all of them intrinsically hazardous. As these gases are transported in huge amounts in dedicated ships equipped with cargo tanks, all safety measures should be taken during its transportation. Gas carriers must comply with the standards set by the IMO (International Maritime Organization) Gas Codes, with all safety and environmental requirements common to other carriers. The main features of their design are the double containment (cargo tanks) and an internal hold (hull). These codes define a distinctive difference between gas carriers and other transporters such as for oil and chemicals. Cargo tanks may be constructed as tanks independent of the hull, being of the self-supporting type or of membrane design. The self-supporting tanks are defined in the IGC Code as being of Type-A, Type-B or Type-C, and the usage of one category or another depends on the type of the trade. Type-A comprises box shaped or prismatic tanks, built to fit to the hull. Type-B is the tank where fatigue life and crack propagation analyses have shown improved characteristics. Such tanks are usually spherical but occasionally may be of prismatic geometry. Type-C is a pressure vessel, often spherical or cylindrical, but sometimes bi-lobe in shape to minimize broken stowage. This work aims to compare qualitatively the three design technologies with their current innovations, i.e., spherical Type B, of Kvaener Moss; membranes Type A, of Gaz Transport and Tecnigaz, namely GTT No. 96, TGZ Mark III and GTT-TGZ CS1; and Prismatic Type B of IHI-SPB, considering carriers with the same capacity and size. The comparison takes into consideration operational, constructive and safety aspects among others, with no quantitative simulations or forecasts about structural integrity, constructive or any other performance numerical parameters.