Abstract: A cleaning system is for cleaning an interior of a subsea structure by use of fluid. The cleaning system has a subsea unit, the subsea unit typically including: a fluids inlet; a hydraulics inlet; a hose, the hose having a nozzle; a feeder for feeding the hose into the interior and for retracting the hose from the subsea structure; and a entry connector for connecting to the subsea structure to be cleaned, through which entry connector the hose may be fed to enter the subsea structure, and a hose reel configured to rotate around a first and a second axis. The rotation around the first axis is for feeding and retracting the water hose and the rotation around the second axis is for rotating the water hose around the its longitudinal axis. A method is for using the cleaning system.