A hyperbaric oxygen chamber is an enclosed space that can be pressurized above one atmosphere (1 ATA) and allow a person to breathe 100% oxygen. The two main types are mono-place chambers and multi-place chambers.

Multi-place chambers are used to accommodate more than one person. Two to 18 people can be inside. The chambers are usually made of steel and can be sphere, igloo or square in shape. They are typically found in hospital settings. Some are equipped with a dual locking system, having a separate chamber that allows medical staff to enter and exit without affecting the pressure in the main treatment area. This allows hands-on monitoring of patients.

The atmosphere can be increased to 6 ATA but compressed air, not oxygen, fills the chamber. Oxygen is delivered via a mask or hood directly to the patient. There are a few drawbacks to the multi-place chamber. With more than one patient, treatment cannot be customized, and all patients within the group receive the same pressure and for the same amount of time. Additionally, the mask/hood might increase anxiety for some patients.

The mono-place chamber, introduced in the 1960s, is designed to accommodate one person at a time and is ideal for clinical settings. The pressure can be increased up to 3 ATA. It is typically cylindrical in shape. More compact than the multi-place chamber, it is composed primarily of acrylic. It is safe and comfortable, and treatment can tailored to the individual patients needs. Oxygen is pumped directly into the chamber and does not require the use of a mask. Close monitoring of the patient occurs from outside of the chamber.

A subset of the mono-place chamber is the portable or mild hyperbaric chamber. It is intended for home use or can be transported when the need arises. It can be used without the assistance of medical staff after initial training. Pressure, however, can only be increased 1.3 ATA and will not be as effective as treatment in a clinical setting.