Atmospheric wetsuits are designed to withstand immense pressure at great depths, allowing divers to remain at normal atmospheric pressure. This eliminates the problems associated with breathing gases at high pressure. Whether recreational or commercial, divers can reach impressive depths with the right equipment, such as a dry wetsuit, dive tank, gloves, etc. Free divers can also dive hundreds of feet underwater without using dive equipment.
With more training and certifications, the maximum depth of immersion will continue to increase. The general consensus is that divers should maintain a slow ascent speed and make a safety stop of 1 to 3 minutes a few meters below the surface before going to the surface. With the advanced open water diving certification, divers can dive to a depth of 30 meters (about 100 feet). The heliox mix can be used for dives of up to 300 meters (984 feet), but if you want to go deeper, you'll have to replace the helium in the tank with hydrogen. You can purposefully overcome the No Decompression Limit (NDL) if you perform a decompression dive with planned decantation stops so that you have more time to safely discharge gas. Deep-sea divers can dive up to 610 m (2000 ft) underwater using specialized equipment, such as atmospheric diving suits (ADS) and dive bells.
With the basic open water certification, a diver can dive to a maximum depth of 18 meters (about 60 feet). According to the PADI (Professional Association of Dive Instructors), the estimated deepest depth that recreational divers can reach is about 130 feet.Dive boards and dive computers help divers understand and calculate how long they can stay at certain depths before their bodies absorb too much nitrogen. Following these tables or using a dive computer can dramatically reduce the likelihood of suffering from decompression sickness. In the world record for deep diving set by Ahmed Gabr, he reported experiencing High Pressure Nervous Syndrome (HPNS) at a depth of 290 m (951 ft).
The maximum limit for what is considered recreational diving is 40 m (130 feet).