The construction of underwater tunnels is a complex process defined by certain factors that determine the project’s viability, safety, and success. The objective of the research paper is to review and analyze the geological, geotechnical, environmental, and human factors that affect the construction of underwater tunnels. In the geological aspect, the kind of soil and rock formations and the groundwater situation are very relevant in determining the most appropriate construction methods. Several site conditions present different geotechnical issues that need engineering solutions to address issues such as water pressure and ground conditions. Technically, tunneling technologies such as TBM and dredging have improved construction effectiveness and security. However, the selection of the right methods has to consider environmental factors such as hydrodynamic forces and impacts on the environment. Other environmental factors include legal factors and sustainability factors. The construction process must also adhere to the ecological effects on marine life to minimize environmental harm. Last, the people involved in the construction workforce and management are crucial for maintaining safety and quality throughout the construction phase. The underwater environment is unique and calls for special training and preventive measures to overcome the difficulties likely to be faced. In conclusion, it is pertinent to understand these influencing factors to undertake proper planning and execution of underwater tunnel projects. The measures that may be taken to enhance the efficiency and safety of future underwater tunnel construction will be discussed in this paper.