The answer, in a word, is "very". Today, you can take a trip on one of over 50 tourist submarines in the world. The fleet has carried over 10 million passengers around the globe during almost thirty eight years of its history, all in superior comfort and safety. The result - the tourist submarine industry has a perfect safety record, without a single serious injury to any passenger.

Assurance of submersible safety begins with the design process. Literally thousands of labour hours are required and hundreds of drawings are generated. Detailed calculations are required in any area of the design. All materials to be used during construction must be certified and specified beforehand. When the design is finally complete it will be exhaustively analyzed by the engineers of the regulatory agency and classification society, and those plans that are satisfactory will be approved. Once all plans have been authorized, construction may commence. Society surveyors are on hand for the construction process. They assure the quality of the materials and the construction techniques. They monitor and witness all the production process. Inspectors also verify the installation and testing of mechanical and electrical systems, check safety devices and examine critical dimensions. The submarines are equipped with several pumps, fire fighting systems and advanced life support system. The craft is in constant contact with the surface support vessel via the underwater sonar communication system, or when surfaced, with a VHF radio. In a brief article it is impossible to describe all the safety features in a contemporary passenger submarine. But the main point is that the industry has a perfect safety record and so, classified passenger submarines are statistically the safest form of transportation in the world today.

The submarine is certified to dive to a maximum depth of 75 meters. The dive site area in the waters surrounding Phuket is thirty meters.