An inflatable floor for an inflatable boat acts as a keel using three inflatable floor layers. The uppermost first inflatable floor layer has a planar cross section. The second inflatable floor layer is located under the first inflatable floor layer. The third inflatable floor layer is located under the second inflatable floor layer. A plurality of threads are provided, in an X- or I-like configuration, inside air chambers of the three inflatable floor layers. The threads link the upper and lower walls of the air chamber of each respective inflatable floor layer to each other. The inflatable floor has increased buoyancy and stiffness, is easy to fold and transport and is easy and economical to repair or replace and thus is easily applicable to a large military or rescue inflatable boat.