A floating element is for forming a modularly constructed buoyancy system. The floating element is provided with a cavity. At least the first side face of the floating element is provided with at least one first cut-out which, at its first end, is connected to a first channel whose mouth is in a first coupling face, and which, at its second end, is connected to a second channel whose mouth is in a second coupling face. A buoyancy system is made up of a plurality of floating elements. A method is for forming such a buoyancy system.