Abstract: A diver's pressure chamber system for use with a pressure chamber having a sealable access and a sealed transfer container for the diver, comprises a tubular projection which is formed around the access of the pressure chamber. In addition, a cylindrical lock space part is hermetically engageable and sealable with the tubular projection and defines, along with the tubular projection, the access, a lock space between the transfer container and the pressure chamber. In one form, the cylindrical lock space part is of substantially the same length as the transfer container and it is held to the projection formed around the access of the main pressure chamber, for example, by a rotatable bayonet-type sleeve catch.