An umbilical cable or umbilical is a cable which supplies necessary requirements to an apparatus. It is named for its similar function to an umbilical cord. An umbilical can supply power to a remote electrical device or a more elaborate design can supply air and power to a spacesuit. Early spacesuits used umbilicals but modern designs carry their own temperature/humidity control, air supply and electric batteries.

Subsea umbilicals are deployed on the seabeds (ocean floors) to supply necessary control and chemicals to subsea oil and gas wells, subsea manifolds and any subsea system requiring a remote control, such as Remotely operated vehicle.

A Diver umbilical cable is a cable which supplies breathing gas and other services from a surface supply to a diver.

For shallow water surface supply air diving, the diver umbilical is typically a 3-part umbilical comprising a gas hose, "pneumo" hose, and diver comms/lifeline cable. The "pneumo" hose is open at the diver's end all the way to a pressure gauge on the surface dive control panel, where the supervisor can see the diver's depth in the water at all times.

A 4-part diver umbilical will also have a hot water supply hose.

A 5-part diver umbilical will also include a Mini Video cable to allow the surface controller to see the video picture transmitted to the surface from the divers hat camera.

For saturation diving from a bell, a typical diver excusion umbilical may be an 8-part umbilical with a gas supply hose, gas reclaim hose, hot water hose, pneumo hose, tracking hose, comms/lifeline cable, Mini Video cable and Hat Light cable.

When there is risk of the umbilical cable being damaged by scratching on rock or coral, the umbilical bundle may be over-braided with a polypropylene braid cover.

Early diver umbilicals were simply the individual components bundled together and taped every metre or so with duct tape. These bundles tend to distort and produce kinks in the components caused by bending (particularly dangerous if the kink is in the divers gas supply hose), and require frequent maintenance. More recent umbilicals comprise all the components cabled together so that there is no chance of a kink, no separate lifeline component is required, and no tape is required to hold the umbilical together. An additional component such as a video cable for a divers camera, or a hat light cable, can be added by manually cabling this into the existing cabled umbilical.