The depth limit of scuba diving is influenced by various factors, and the depth limit for recreational scuba diving is usually set at around 40 meters. This is a comprehensive consideration of various factors such as human physiological endurance, diving equipment performance, and diving safety.

When a recreational diver is at a depth of 40 meters, the pressure on their body is about 5 times that of the surface pressure. At this time, the risk of nitrogen intoxication increases significantly, which may cause the diver to have blurred thinking, uncoordinated movements, and pose a serious threat to diving safety. Meanwhile, ordinary scuba equipment may also experience performance degradation or malfunction in deeper waters.

However, after professional training and the use of special equipment, technical divers can dive to deeper depths, typically up to 100 meters or even deeper. However, diving at such depths carries extremely high risks and requires extensive experience, professional skills, and comprehensive safety measures.