Abstract: A folding pontoon arrangement comprises one, or preferably two pairs of pontoons. The pontoons in each pontoon pair are mutually, pivotably connected about a hinge line at the upper side of the pontoons. One of the pontoons of each pair has a chamber situated below the hinge line, which can be opened to the outside of the pontoon via a closable connection. The second pontoon in the pontoon pair has a wheel housing with a ground wheel mounted therein under the hinge line. When the pontoon pair assumes an extended floating position and the connection is then opened, the chamber is filled with water causing the pontoon pair to fold about the hinge line. The weight of the wheel contributes to the folding tendency. If two pontoon pairs are pivotably interconnected with the aid of a third hinge joint, a pontoon unit is obtained which is a self-contained vehicle on the wheels when the pontoons are locked together in an upstanding, juxtaposed position.