A pontoon bridge, also known as a floating bridge, uses floats or shallow-draft boats to support a continuous deck for pedestrian and vehicle travel. The buoyancy of the supports limits the maximum load they can carry. Most pontoon bridges are temporary, used in wartime and civil emergencies.

Floating bridges are made of large water-tight concrete pontoons connected rigidly end-to-end, upon which the roadway is built. Despite their heavy concrete composition, the weight of the water displaced by the pontoons is equal to the weight of the structure (including all traffic), which allows the bridge to float.