A decompression chamber is a pressure vessel used in surface supplied diving to allow the divers to complete their decompression stops at the end of a dive on the surface rather than underwater. This eliminates many of the risks of long decompressions underwater, in cold or dangerous conditions.

Often the terms "decompression chamber", "recompression chamber" and "hyperbaric oxygen therapy chamber" are used interchangeably. The names reflect the different purposes that the chambers are designed for, rather than their capability. Each is capable of operating in the others' role:

• a recompression chamber is used to treat divers suffering from certain diving disorders such as decompression sickness
• a hyperbaric oxygen therapy chamber is used in a hospital or sporting context to treat patients whose condition might benefit from hyperbaric oxygen treatment, including divers.