The invention relates to an apparatus for transferring data and to a method for transferring data from or to an underwater pressure body 30 having a bulk storage apparatus 10. The bulk storage apparatus 10 is normally located within the underwater pressure body 30, such that only by means of a time-consuming disassembly of the underwater pressure body 30 can the bulk storage apparatus 10 be disconnected from a computation unit 32 of the underwater pressure body 30, and the data of the separate bulk storage apparatus 10 can be transferred by passing on to the bulk storage apparatus 10. The problem of time-consuming transfer of data is solved by means of an apparatus according to the invention which comprises the bulk storage apparatus 10, which has a pressure-resistant insulation body 24 through which water cannot pass and which has no air in it, and which can be detachably connected to a connecting apparatus 36 which is arranged on the outside of the underwater pressure body 30. There is therefore no need to disassemble the underwater pressure body 30 in order to remove the bulk storage apparatus 10, and the time for transferring the data is substantially shortened.